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This  book  is  due  on  the  date  indicated 
below  and  is  subject  to  an  overdue  fine 
as  posted  at  the  Circulation  Desk. 


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THE  MEANING  OF  EVOLUTION 


^^ 


THE  MACMILLAN   COMPANY 

NBW  YORK   •    BOSTON   •    CHICAGO 
DALLAS   •    ATLANTA   •    SAN   FRANCISCO 

MACMILLAN  &  CO.,  Limitkd 

LONDON   •    BOMBAY  •    CALCUTTA 
MELBOURNE 

THE  MACMILLAN  CO.  OF  CANADA,  Ltix 

TORONTO 


CHARLES  ROBERT  DARWIN 

(1809-1S82) 

Persuaded  the  scientific  world  of  the  truth  of  evolution. 

[Frontispiece] 


THE  MEANING  OF 
EVOLUTION 


BY 

SAMUEL  CHRISTIAN  SCHMUCKER,  Ph.D. 

PROFESSOR    OF    BIOLOGICAL    SCIENCES    IN    THE 

WEST  CHESTER  STATE  NORMAL  SCHOOL 

WEST  CHESTER,  PA. 


J9ehJ  govk 
THE   MACMILLAN   COMPANY 


Copyright,  1913 
By  the  MACMILLAN  COMPANY 


Set  up  and  electrotyped.    Published  September,  191? 


CONTENTS 

A  Foreword     .    .    . 


CHAPTER 

PAGE 


I 

I.    Evolution  Before  Darwin 

II.    Darwin  and  Wallace 

III.  The  Underlying  Idea  ... 

44 

IV.  Adaptation  for  the  Individual §7 

V.    Adaptation  for  the  Species 125 

VI.    Life  in  the  Past.    .    . 

149 

VII.  How  the  Mammals  Developed 102 

VIII.  The  Story  of  the  Horse 220 

IX.  Evolution  Since  Darwin 233 

X.  The  Future  Evolution  of  Man 249 

XL  Science  and  the  Book 274 

Index 

293 


MOPERTY  OF 

i;%M.COaEGE  LIBRARY. 


6o-[t 


LIST   OF    ILLUSTRATIONS 


FACING 
.  PAGE 


Charles  Robert  Darwin  (1809-188 2) Frontispiece 

The  Chevalier  de  Lamarck  (i 744-1829) 18 

Phenacodus,  an  Early  Generalized  Mammal 224 

The  Dawn  Horse 224 

The  Three-toed  Horse 228 

The  American  Horse 228 

August  Weismann  (1834) 238 

Hugo  de  Vries    .      .      .' 246 


A    FOREWORD 

Before  my  window  lies  an  enchanting  landscape. 
It  embraces  a  stretch  of  open  rolling  country,  beauti- 
ful  as  the  eye  could  wish  to  rest  upon.     The  sun 
with  its  slanting  rays  is  not  giving  it  heat  enough  in 
these  winter  months  to  make  it  blossom  in  its  radiant 
beauty,  but  the  mind  goes  easily  back  through  the 
few  brown  months  to  the  time  when  the  field  not  far 
away  was  waving  with  its  rich  yellow  grain  so  soon 
to  be   food   for  those  who  planted  it.     Beyond  this 
field  lies  an  orchard  where,   in  regular  and  orderly 
rows,  stand  the  apple  trees  whose  bright  blossoms  in 
the  spring  make  the  landscape  so  beautiful  and  whose 
fruit  in  the  fall  serves  so  richly  for  our  enjoyment. 
A  little  farther  on,  a  pasture  is  filled  with  sleek-coated 
cows,  feeding  quietly  and  patiently  until  the  evening 
when  they  will  return  to  their  stalls  to  yield  their  rich 
milk.     Still   farther  on  lies  a  tract  of   forest.     The 
varied  shades  of  the  beeches,  the  tulip  poplars  and 
the  chestnuts  make  an  exquisite  contrast  and  give  to 
the  landscape  its  attractive  background  framed  in  by  a 
distant  hill.     Behind   this   hill  flows  a  mighty  river 
carrying  on  its  breast  the  ships  by  which  we  share 

I 


2  THE    MEANING    OF    EVOLUTION 

the  over-abundance  of  our  own  blessings  with  our 
brothers  on  the  other  side  of  the  sea,  from  whom  in 
turn  we  receive  of  their  overplus.  Beyond  this  teem- 
ing river  lies  a  level  stretch  of  fertile  land  and  then 
the  mighty  ocean.  On  one  side  of  the  scene  runs  a 
busy  highway.  Along  this  men  pass  and  repass,  some 
on  foot,  others  drawn  by  their  patient  and  submissive 
horses.  Still  others  are  carried  by  the  new-found 
power  of  the  sunshine  imprisoned  beneath  the  rocks 
in  the  oil  that  has  been  forming  ever  since  the  sun 
shone  down  upon  the  great  forests  of  the  far  dis- 
tant past. 

In  a  pathway  to  one  side,  some  children  are  play- 
ing. One  of  them  has  laid  upon  the  ground  a  rec- 
tangle of  stones  divided  into  four  and  her  little  mind 
sees  before  her  the  house  which  is  teaching  her  to  get 
ready  for  the  work  that  shall  come  to  her  in  later 
life.  Meanwhile  her  short-haired  companion  is  pranc- 
ing around  astride  a  stick ;  he  too,  little  as  he  suspects 
it,  is  getting  ready  for  life. 

It  needs  little  reflection  to  realize  that  the  scene  has 
not  always  been  what  it  is.  The  underlying  ground 
has  surely  been  there  longest,  its  age  vying  only  with 
that  of  the  bounding  ocean  that  beats  upon  the  shore 
and  works  the  sand  into  fantastic  stretches.  The 
forest  has  been  there  long  and  so  has  the  stream; 
the  road  perhaps  ranks  next  in  age;  then  come  the 


A    FOREWORD  3 

orchard  trees,  and  most  recent  of  all  the  waving  grain. 
People  come  and  go  but  form  no  stable  part  of  this 
landscape.  We  know  how  the  grain  came  to  be  there, 
and  we  understand  the  orderly  arrangement  of  the 
orchard  trees;  the  road  too  we  can  explain.  How 
came  the  stream  there,  and  how  the  forest  trees? 
Have  they  always  been  there,  or  did  they  too  have  a 
beginning?  Was  there  a  time  when  there  was  no 
ocean  ?    When  was  this  time  ?    How  came  they  there  ? 

When  the  lisping  lips  of  my  young  child  asked  me, 
'Tapa,  who  made  me?"  I  told  him  "God,"  and  he 
knew  enough  and  was  content  with  his  knowledge. 
After  a  while  he  grew  older  and  his  inquisitive  spirit 
began  to  puzzle  with  the  question  of  how  God  had 
made  him.  When  his  growing  mind  was  ready  for 
the  new  knowledge  I  took  him  to  my  side  and  told 
him  the  great  mystery  of  life.  I  told  him  how  he 
owed  to  his  father  and  to  his  mother  the  beginnings 
of  his  life,  how  God  gave  him  to  us.  Now  a  new  era 
opened  in  his  childish  mind.  As  he  grows  on  to 
greater  maturity  he  cannot  help  wondering  how  the 
first  man  was  made,  how  the  trees,  and  the  world  came 
to  be.  He  is  no  longer  satisfied  with  the  simple  state- 
ment that  God  made  them.  His  eager  mind  wants  to 
know,  if  may  be,  how  God  made  them. 

So,  in  the  distant  past,  in  the  childhood  of  our  race, 
the  question  was  asked,  ''Who  made  us  ?"  and  the  an- 


4  THE    MEANING    OF    EVOLUTION 

swer  was  "God."  Men  formed  their  simple  concep- 
tion at  that  time  of  how  He  did  it.  As  the  centuries 
rolled  by  and  the  children  of  men  have  learned  from 
creation  the  story  of  its  origin  a  riper  and  richer 
knowledge  has  given  them  a  broader  and  finer  con- 
ception. No  less  does  the  reverent  student  believe 
that  God  created  the  earth,  but  he  no  longer  thinks  of 
God  as  working,  as  man  works.  He  no  longer  feels 
that  it  is  impious  to  attempt  to  read  God's  plan  in  His 
work ;  to  see  how  this  work  has  arisen,  to  see,  if  may 
be,  what  there  is  ahead. 

This  is  one  of  the  tasks  to  which  science  is  now 
giving  itself.  The  answer  is  uncertain  and  halting. 
A  few  things  seem  clear;  others  seem  to  be  nearly 
certain;  of  still  others  we  can  only  say  that  for  the 
present  we  must  be  content  with  the  knowledge  we 
have.  But  if  we  take  the  best  we  have  and  work 
over  it  thoughtfully  and  carefully,  the  better  will 
slowly  come,  and  in  time  we  shall  know  far  more  than 
we  now  suspect.  Meanwhile,  it  is  the  attempt  of  this 
book  to  give  to  people  whose  training  is  other  than 
scientific  some  conception  of  this  great  story  of  cre- 
ation. Without  dogmatic  certainty  but  without  inde- 
cision it  tries  to  tell  what  modern  science  thinks  as  to 
the  great  problems  of  life.  It  tries  to  describe  the 
possible  origin  of  animals  and  plants,  their  slow  ad- 
vance, the  length  of  their  steady  uplift,  the  forces  that 


A    FOREWORD  5 

brought  it  about.  It  tries  to  tell  a  little  of  the  men 
who  have  helped  to  develop  the  great  idea  of  evo- 
lution, of  the  great  men  who  persuaded  the  scientific 
world  of  its  truth,  and  of  the  later  minds  that  are 
modifying  and  enlarging  the  idea  of  the  master  evo- 
lutionist. It  tries  to  tell  what  science  perhaps  vaguely 
hopes  as  to  the  future.  What  are  we  to  be  ?  Can  we 
help  the  great  advance  ? 


THE  MEANING  OF  EVOLUTION 


. 


The  Meaning  of  Evolution 

CHAPTER    I 

Evolution  Before  Darwin 

Ever  since  men  have  been  able  to  think  they  must 
have  puzzled  out  for  themselves  some  way  of  ac- 
counting for  their  own  beginnings.  Every  savage 
tribe  with  whom  we  have  any  intimate  acquaintance 
has  some  story  that  accounts  for  the  origin  of  the 
tribe  at  least,  and  often  for  the  beginning  of  the 
world.  These  stories  are  handed  down  from  genera- 
tion to  generation  and  are  scarcely  questioned  in  the 
thought  of  most  men.  In  early  Greece  there  was  a 
succession  of  men  whom  the  world  calls  philosophers. 
These  men  thought  earnestly  and  deeply  on  all  kinds 
of  questions.  Their  method  was  not  our  method. 
The  plan  of  making  a  long  series  of  observations, 
before  coming  to  any  conclusion,  was  not  the  habit 
of  their  minds.  They  reasoned  out  on  general  prin- 
ciples what  seemed  to  them  must  have  been  the  origin 
of  the  world.  It  is  not  strange  that  among  these 
should  come,  now  and  then,  some  one  who  in  some 

7 


8  THE    MEANING    OF    EVOLUTION 

passage  or  other  should  show  that  there  had  come 
to  his  mind  at  least  a  glimmer  of  the  thought  that 
was  later  to  develop  into  the  great  idea  which  the 
modern  world  calls  evolution. 

Among  the  earliest  of  these  was  Anaximander, 
who  lived  600  years  before  Christ.  He  thought  that 
the  earth  was  at  first  a  fluid.  Gradually  this  fluid 
began  to  dry  and  grow  thicker,  and  here  and  there, 
where  it  thickened  most,  dry  land  appeared.  When 
this  dry  land  had  become  firm  enough  to  serve  as 
his  home,  man  came  up  from  the  water  in  the  form 
of  a  fish.  Slowly  and  gradually  the  fish,  struggling 
about  on  the  land,  gained  for  himself  the  limbs  and 
members  he  needed  for  his  new  situation  and  devel- 
oped into  a  man.  After  him  other  animals  came  up 
in  much  the  same  fashion,  then  the  plants,  until  the 
whole  world  was  clothed  with  its  present  inhabitants. 

One  hundred  and  fifty  years  later  Empedocles  an- 
nounced a  new  thought.  He  said  that  in  the  begin- 
nings there  were  all  sorts  of  strange,  incomplete,  and 
misjointed  monsters  wdiich  swarmed  upon  the  earth, 
having  sprung  up  out  of  the  earth  itself.  Each  was 
a  chaos  of  the  limbs  which  afterward  were  to  belong 
to  other  animals  which  needed  them  more.  Slowly 
and  gradually  an  interchanging  came  about  by  which 
appropriate  limbs  fastened  themselves  to  the  proper 
animals.    The  last  of  these  misjointed  creatures  is  the 


EVOLUTION    BEFORE   DARWIN  9 

one  known  as  the  centaur,  half-man — half-horse. 
After  a  Avhile,  when  all  the  members  had  found  their 
proper  places,  the  animals  were  complete.  In  one  re- 
spect this  opinion  foreshadowed  our  later  idea.  It 
suggested  that  the  more  perfect  animals  had  arisen 
out  of  the  less  perfect  and  that  the  change  came 
gradually. 

Then  came  Anaxagoras,  who  was  the  first  to  be- 
lieve that  there  was  intelligent  design  back  of  the 
creation  of  animals  and  of  plants.  He  thought  there 
had  originally  been  a  slime  in  which  were  the  germs 
of  all  the  later  plants,  animals,  and  minerals,  mixed 
in  a  chaos.  Slowly  order  arose.  Out  of  the  mix- 
ture settled  first  the  minerals  forming  the  earth,  with 
the  air  floating  above  it,  and  above  the  air  was  the 
ether.  Out  of  the  air  the  germs  of  plants  settled 
upon  the  earth,  and  vegetation  covered  the  mineral 
floor.  Then  from  the  ether  came  the  germs  of  ani- 
mals and  of  men.  These  settled  among  the  plants  and 
sprang  up  into  the  animals  of  the  world,  as  well  as 
the  people. 

The  greatest  scientific  thinker  of  early  Greece  was 
Aristotle.  He  had  lived  by  the  seashore  and  knew 
better  than  any  other  man  of  his  times  the  exquisite 
seaweeds  and  the  still  more  beautiful  marine  animals. 
He  was  the  first  to  think  of  them  as  a  linked  series, 
the   higher  developing  out   of   the  lower  under  the 


lO  THE    MEANING    OF    EVOLUTION 

pressure  of  wliat  he  called  a  perfecting  principle.  Out 
of  the  inanimate  rocks  had  sprung  the  marine  plants 
— the  seaweeds.  From  these  had  developed  first 
''plant  animals"  like  the  sea  anemones  and  the  sponges. 
These  grew  attached  to  the  rocks,  as  plants  do.  With 
higher  development  came  locomotion,  with  ever-in- 
creasing energy.  At  last  man  arose,  the  crown  of  all 
creation.  Presiding  over  all  this  advance  is  the  ''effi- 
cient cause,"  God.  Aristotle  rejected  entirely  the  ear- 
lier ideas  that  any  of  this  work  came  about  by  chance. 
He  was  certain  of  the  existence  of  plan  and  purpose 
in  the  development. 

Just  a  little  before  the  time  of  Christ  the  Latin 
poet,  Lucretius,  wrote  a  poem  on  "The  Nature  of 
Things."  Here  he  describes  how  in  the  early  years 
the  beginnings  of  things  in  small,  disjointed  fashion 
moved  about  among  each  other  at  first  in  utter  con- 
fusion, each  trying  itself  with  the  other.  After  many 
trials  the  proper  members  came  together.  When  they 
had  been  thus  placed  the  warmth  of  the  sun  shining 
down  upon  the  earth  helped  the  earth  to  reproduce 
the  same  sort  of  creatures.  So  living  things  came 
up  and  flourished.  The  poem  expresses  many  beauti- 
ful ideas,  but  the  underlying  conceptions  lack  the  unity 
and  grandeur  that  marked  Aristotle's  work,  which 
later  was  the  potent  influence  in  shaping  men's  minds. 
It  died  out  after  a  while,  only  to  awake  in  the  Re- 


EVOLUTION    BEFORE   DARWIN  II 

naissance  with  marvelous  vitality,  starting  the  world 
to  think  afresh  great  thoughts  that  would  not  die,  but 
would  grow  from  that  time  on  with  ever-widenin^- 
scope. 

Among  the  Jews  and  early  Christians  the  stately 
and  beautiful  account  in  Genesis  sufficed  for  all  the 
needs  of  minds  fully  occupied  with  other  questions. 
With  the  growth  of  philosophy  among  Christian 
minds  again  came  the  need  of  a  satisfactory  solution. 
St.  Augustine  was  probably  the  greatest  of  the  so- 
called  "Fathers"  of  the  church.  His  mind  was  emi- 
nently philosophical,  and  he  was  learned  in  the  writ- 
ings of  the  older  Greeks.  He  believed  the  language 
of  Genesis  to  mean  that  in  the  beginning  God  planted 
in  chaos  the  seed  that  afterward  sprang  up  into  the 
heavens  and  the  earth.  He  further  says  that  the  six 
days  of  creation  were  not  days  of  time,  but  a  series 
of  causes,  and  that,  in  the  order  described  as  these 
six  days,  God  planted  in  chaos  the  various  beginnings 
of  things.  These  in  the  fullness  of  time  sprang  up 
into  the  world  as  we  know  it  now.  The  problem  was 
not  a  question  about  which  the  church  cared  to  trouble 
itself,  and  with  the  oncoming  of  the  Dark  Ages  the 
whole  matter  dropped  nearly  out  of  the  thoughts  of 
men. 

When  the  times  began  to  lighten  we  find  the  school- 
men,   among    the    greatest    of    whom    was    Thomas 


12  THE    MEANING    OF    EVOLUTION 

Aquinas.  Referring  especially  to  the  authority  of  his 
master,  St.  Augustine,  he  says  that  it  would  be  easy 
mistakenly  to  believe  that  the  author  of  Genesis  meant 
to  convey  the  idea  that  on  each  of  the  six  days  cer- 
tain acts  of  creation  were  performed.  It  is  quite  evi- 
dent, thinks  Aquinas,  that  in  those  early  times  God 
only  created  the  germs  of  things  and  put  into  the 
earth  powers  which  should  later  become  active.  Af- 
ter the  Creator  had  thus  endowed  the  earth  he  rested 
from  the  work,  which  proceeded  to  develop  under 
the  influence  of  these  first  germs. 

Nearly  four  hundred  years  later,  when  Europe  had 
finally  awakened  out  of  the  deep  and  refreshing  sleep 
in  which  it  had  fortunately  forgotten  much  of  the 
past,  a  new  era  dawned  and  modern  thought  began. 
Immediately  men  commenced  to  busy  their  minds  with 
broader  problems  than  they  had  been  discussing  since 
the  time  of  the  Greek  philosophers.  The  hand  of 
tradition,  however,  was  heavy  on  them  still.  They 
dreaded  to  run  counter  to  authority,  and  did  not  dare 
think  unrestrainedly.  Descartes  shows  us  how  we  can 
understand  things  better  if  we  will  imagine  a  few 
principles  by  which  it  will  be  easy  to  account  for 
things  as  they  are.  Then  he  carefully  elaborates  these 
principles  as  they  occur  to  him ;  but  he  has  no  sooner 
done  so  than  he  takes  care  to  add,  ''Of  course,  we 
know  the  earth  was  not  made  in  this  way." 


EVOLUTION    BEFORE   DARWIN  1 3 

A  little  later  the  philosopher,  Leibnitz,  believed  in 
an  orderly  creation  that  had  advanced  by  regular  de- 
grees, and  that  the  lower  animals  had  thus  developed 
into  the  higher.  He  adds  interestingly  that  there  are 
probably  on  some  other  planets  animals  midway  be- 
tween the  ape  and  man,  but  that  nature  has  kindly 
removed  such  animals  from  the  earth  in  order  that 
man's  superiority  to  the  apes  should  be  entirely  be- 
yond question. 

By  the  middle  of  the  eighteenth  century  men  had 
begun  to  think  more  fearlessly.  The  great  Emanuel 
Kant  wrote  in  his  younger  and  less  timid  years,  "The 
General  History  of  Nature  and  Theory  of  the  Heav- 
ens." The  great  Newton  had  by  his  law  of  gravita- 
tion brought  order  into  the  heavens.  Kant  looked 
longingly  for  a  greater  Newton,  who  should  find  a 
similar  unity  in  the  animal  world.  He  saw  the  won- 
derful likenesses  between  animals  that  the  anatomist, 
Buffon,  had  recently  pointed  out.  He  believed  there 
must  somehow  be  blood  relationship  between  all  ani- 
mals. He  tried  hard  to  conceive  of  some  underlying 
natural  cause  by  which  all  could  have  come  about. 
As  he  grew  older  and  his  mind  became  more  cautious 
he  came  to  think  the  matter  deeper  than  the  human 
mind  could  ever  fathom.  He  gave  up  the  hope 
and  believed  the  problem  of  animal  origin  and  deri- 
vation  would   forever  remain  insoluble.     He   feared 


14  THE    MEANING    OF    EVOLUTION 

there  was  not  in  man  the  power  to  conceive  his  own 
origin. 

If  w^e  ever  wonder  why  it  took  so  long  before  the 
thought  of  evolution  should  have  fully  dawned  upon 
the  world,  the  answer  is  not  far  to  seek.  No  student 
of  Natural  History  in  ancient  or  medieval  times  had 
the  faintest  conception  of  the  enormous  number  of 
animals  and  of  plants  in  the  world.  The  old  Greek 
or  Roman  student  of  Natural  History  gives  no  evi- 
dence of  knowing  more  than  a  few  hundred  ani- 
mals. Men  have  named  to-day,  with  systematic  Latin 
names,  hundreds  of  animals  for  every  one  that  Pliny 
ever  knew,  and  he  knew  more  than  any  other  man 
of  early  times  of  whom  record  has  come  to  us. 

In  early  days  men  who  traveled  into  foreign  coun- 
tries brought  back  accounts  of  what  they  saw.  The 
whole  Natural  History  of  ancient  times  was  filled 
with  the  most  absurd  and  ludicrous  stories  of  all  sorts 
of  things  to  be  seen  in  distant  lands.  Sir  John  Man- 
deville  tells  tales  almost  as  imaginative  and  quite  as 
amusing  as  those  attributed   to   Baron   ]\Iunchausen. 

Upon  the  great  awakening  of  the  fifteenth  century, 
with  its  new  study  and  its  wide-ranging  travel,  an 
entire  change  came  over  the  human  mind.  Men  who 
journeyed  into  far  countries  brought  back  with  them 
not  only  accounts  of  what  they  saw,  but,  so  far  as 
might  be,  the  things  themselves.     Collections  of  plants 


EVOLUTION    BEFORE   DARWIN  1 5 

and  of  such  parts  of  animals  as  could  be  readily  pre- 
served soon  began  to  accumulate  in  every  great  center 
of  Europe.  It  was  only  a  question  of  time  when  such 
accjuisitions  must  be  arranged  and  classified,  but  as 
yet  there  was  no  system  by  which  this  could  be  done. 
The  great  Swedish  botanist,  Linnseus,  who  lived  in 
the  eighteenth  century,  first  taught  us  to  give  to  each 
animal  and  plant  two  Latin  names,  the  first  of  these 
to  be  the  name  of  the  group,  known  as  a  genus,  to 
which  it  belongs,  the  second  to  be  the  name  of  that 
sort,  or  species,  of  animal.  The  cat,  for  instance,  is 
Felis  catus,  the  lion  Fclis  leo,  the  tiger  Felis  tigris, 
and  so  on.  Linnceus  then  arranged  the  genera  (plural 
of  genus)  into  families,  and  these  families  into  orders 
and  so  classified  the  animal  and  plant  world  as  far  as 
he  knew  it.  In  his  earlier  years  Linnaeus  thought  of 
each  species  as  being  utterly  apart  and  distant  from 
any  other.  He  believed  it  had  been  so  from  the  first, 
each  species  having  sprung  in  its  complete  form  from 
the  creative  hand  of  God.  In  later  life  he  came  to 
show  some  evidence  of  the  belief  in  development,  but 
his  great  work  is  all  built  on  the  idea  of  the  entire 
fixity  of  species. 

About  this  time  we  find  in  the  writings  of  Bufifon, 
the  French  naturalist,  many  indications  of  an  idea 
approaching  our  modern  conceptions  of  evolution.  He 
felt  sure  the  pig  could  not  have  been  a  special  crea- 


l6  THE    MEANING    OF    EVOLUTION 

tion,  because  he  had  four  toes,  two  of  which,  with  all 
their  bones  and  their  hoofs,  are  quite  useless  to  him. 
We  now  call  these  toes  "vestigial,"  and  know  the 
pig's  ancestors  used  them,  walking  on  four  toes  and 
not  on  two,  as  at  present.  Buffon  believed  there  were 
degenerations  as  well  as  developments,  and  considered 
the  ape  a  degenerate  man.  He  conceived  these 
changes  to  be  brought  about  by  what  he  called  the 
favors  and  disfavors  of  nature.  He  varied  much  in 
his  opinions  in  various  parts  of  his  career  and  occa- 
sionally is  smitten  either  with  conscience  or  with  fear 
of  authority.  Then  he  goes  back  and  says  it  is  all  a 
mistake  and  each  animal  is  the  product  of  a  special 
act  on  the  part  of  the  Creator. 

A  little  later,  in  England,  Erasmus  Darwin,  the 
grandfather  of  Charles  Darwin,  who  was  subse- 
quently to  establish  the  evolution  theory,  wrote  a  long 
and  elaborate  poem  called  the  "Temple  of  Nature." 
In  this  we  find  a  remarkable  prevision  of  many  of  the 
principles  which  were  afterward  to  be  warmly  advo- 
cated and  disputed  during  the  growth  of  the  idea  of 
evolution. 

"Hence  without  parents  by  spontaneous  growth, 
Rise  the  first  specks  of  animated  life. 

^^  ^^  ^%  ^^  ^T^  ^^^  ^^^ 

Thus  as  successive  generations  bloom 

New  powers  acquire  and  larger  limbs  assume." 


EVOLUTION    BEFORE   DARWIN  1 7 

Erasmus  Darwin  recognized  the  struggle  for  exist- 
ence, but  he  saw  in  it  only  a  check  against  overcrowd- 
ing, and  not  an  active  factor  in  the  development  as  his 
grandson  Charles  came  to  see  it.  It  is  possible  the 
elder  Darwin's  views  might  have  been  taken  more 
seriously  had  he  not  clothed  them  with  the  form  of 
verse.  In  these  days  it  seems  quite  ludicrous  to  think 
of  giving  to  the  world  a  new  scientific  concept  or  a 
new  phase  of  philosophy  in  verse. 

The  beginning  of  the  nineteenth  century  gives  us 
the  first  really  great  contribution  to  the  idea  of  evolu- 
tion. Under  more  favorable  surroundings,  this  idea 
would  have  budded  and  become  the  parent  stock  of 
our  modern  theories.  The  chill  frosts  of  adverse 
criticism  by  those  in  authority  in  science  nipped  the 
budding  idea  and  so  set  it  back  that  only  of  late  years 
have  men  come  to  realize  its  strength  and  power. 
The  Chevalier  de  Lamarck,  serving  in  Monaco,  was 
attracted  by  its  rich  flora  to  the  study  of  botany. 
Coming  later  to  Paris,  he  became  acquainted  with 
Buffon  and  was  led  by  him  to  publish  a  Flora  of 
France,  using  the  Linnaean  system  of  classification. 
He  was  appointed  to  the  chair  of  zoology  in  the  Jar- 
din  des  Plantes,  and  was  given  especial  charge  of  the 
invertebrate  animals,  comprising  all  the  members  of 
the  animal  kingdom  except  those  with  backbones. 
After  seventeen  years  of  work  over  these  forms,  dur- 


l3  THE    MEANING    OF    EVOLUTION 

ing  which  he  wrote  several  books  describing  them,  he 
finally  published  the  great  work  on  which  his  fame 
depends.  This  was  the  "Philosophic  Zoologique." 
In  this  treatise  he  taught  that  the  animal  kingdom  is 
a  unit  and  that  all  its  members  are  blood  relations ; 
that  the  members  vary  wnth  varying  conditions ;  that 
this  variation  results  in  continued  advance.  In  all  of 
these  points  Lamarck  is  at  one  with  modern  thought. 
His  idea  of  the  method  by  which  the  variation  comes 
about  has  been  accepted  and  rejected;  modified,  re- 
accepted,  and  again  rejected. 

Lamarck's  conception  of  the  cause  of  progress  was 
somewhat  as    follows:      The   desire    for   any   action 
on  the  part  of  an  animal  leads  to  efforts  to  accom- 
plish that  desire.     From  these  efforts  came  gradually 
the  organ  and  its  accompanying  powers.     With  every 
exercise  of  these  powers  the  organ  and  its  correspond- 
ing  function  became  better  developed.     Every  gain 
either   in   function   or   in   organ   was   transmitted   to 
those  of  the  next  generation,  who  were  thus  enabled 
to   start  where  their  parents   left  off.     The  general 
environment  constantly  gave  the  stimuli  that  led  to 
the  adaptive  changes. 

American  zo51ogists  have  been  especially  inclined 
toward  Lamarck's  ideas.  Until  Weismann  startled 
the  scientific  w^orld  with  his  sharp  denial  of  the  pos- 
sibility of  transmitting  to  offspring  any  growth  ac- 


THE  CHEVALIER  DE  LAMARCK 
(1744-1829) 
The  greatest  evolutionist  before  Darwin. 


[Facing  i8j 


i 


EVOLUTION    BEFORE    DARWIN  Iq 

quired  by  the  parents,  all  seemed  well.     There  is  a 
tendency   now  to   insist   once  more  that  slowly  and 
gradually,  in  some  perhaps  as  yet  unexplained  way, 
external  factors  do  influence  even  egg  cells,  and  grad- 
ually acquired  characters  do  reappear  in  the  offspring. 
The   blighting  setback   these  views  suffered   can^e 
from  the  criticisms   of   Baron   Cuvier.      This   genu- 
inely remarkable  man  had  built  up  the  study  of^com- 
parative  anatomy.     To  him  students  flocked  from  all 
sides.  ^  Among  these  one  of  the  most  brilliant  was 
Agassiz,  the  Swiss  naturalist,  who  later  came  to  this 
country,  filled  with  Cuvier's  ideas.    This  great  teacher 
believed  that  species  are  fixed.     He  knew  better  than 
any  man  of   his   times   the   wonderful   similarity   in 
structure  between  animals  of  a  given  class.     He  at- 
tributed this  not  to  any  real  blood  relationship  be- 
tween the   animals.     They  were  alike  because  they 
had   been  made   by   the   same   Creator.     This   great 
Artificer  worked   along   four  main  lines,   and  hence 
animals  could  be  divided   into   four  groups.     Many 
who  have  studied  text  books  on  zoology  written  in 
this  country  by  Agassiz  and  his  followers  will  remem- 
ber   the    four    classes— Radiates,    Articulates,    Mol- 
lusks,  and  Vertebrates.     Agassiz  was  such  a  wonder- 
ful teacher  and  so  genial  and  so  lovable  a  man  that 
his  opposition  to  evolution  held  back  the  advance  of 
the  Darwinian  idea  in  America  as  Cuvier's  influence 


20  THE    MEANING    OF    EVOLUTION 

had  held  hack  the  Lamarck ian  idea  in  Europe.     For 
the  hrilhant   Ciivier  simply   laughed   hefore  his   stu-  v 
dents  at  each  ''new  folly"  of  Buffon  and  of  Lamarck.  "* 
Under  this  ridicule  the  influence  of  both  men  with- 
ered and  died. 

A  little  later  the  great  poet,  Goethe,  turned  his 
attention  to  the  problem  of  evolution,  giving  an  in- 
teresting account  of  the  metamorphoses  of  plants.  He 
declared,  also,  that  the  human  skull  is  a  continuation 
of  the  backbones  of  the  neck,  and  that  these  bones 
have  been  transformed  into  the  present  skull.  But 
his  great  genius  as  a  poet  drew  his  attention  into 
other  fields.  Haeckel  points  out  that  if  Goethe  had 
known  Lamarck's  work  his  genius  would  have  gained 
for  the  "Philosophie  Zoologique"  the  interest  and  re- 
spect of  the  reading  world.  But  Cuvier  laughed  it 
out  of  court,  and  only  in  comparatively  modern  times, 
since  Darwin's  work  has  set  the  world  thinking  anew, 
is  Lamarck's  career  recognized  at  its  true  value. 
Lamarck  should  have  been  the  founder  of  the  evolu- 
tion theory.  But  the  time  was  not  quite  ripe,  and  it 
remained  for  Charles  Darwin  to  announce  his  idea, 
sustained  and  fortified  by  years  of  careful  observation 
and  thoughtful  reflection. 


CHAPTER    II 

Darwin  and  Wallace 

We  have  seen  in  the  last  chapter  that  whenever 
men  have  actively  thought  they  have  attempted  to 
explain  the  origin  of  plants  and  animals  as  well  as 
of  themselves.  No  one  who  wrote  previous  to  the 
time  of  Charles  Darwin  had  expressed  any  idea  con- 
cerning this  matter  with  force  enough  to  convince 
any  large  portion  of  the  thinking  world,^  If  Lamarck 
had  fallen  on  better  times,  if  the  great  Cuvier  had  not 
laughed  him  to  scorn,  if  Goethe  had  found  him  out 
and  made  him  known  to  the  world,  evolution  might 
have  come  into  its  own  sooner.  None  of  these  con- 
ditions arose,  and  it  remained  for  Charles  Darwin 
to  give  to  the  world  in  clear  and  cogent  form  the 
thought  of  evolution,  tie  gathered  so  much  material 
before  he  expressed  his  opinions,  and  looked  at  the 
matter  from  so  many  sides  that,  when  he  published 
his  results,  he  had  foreseen  most  of  the  objections 
which  were  subsequently  to  arise  in  opposition  to  his 
announcement.^  Charles  Darwin  is  recognized  to-day 
as  the  father  of  the  evolution?-ry  movement. 

21 


22  THE    MEANING    OF    EVOLUTION 

It  has  been  sometimes  said  in  recent  years  that  Dar- 
winism is  dead,  and  there  is  a  sense  in  which  this  is 
true.  Unmodified  and  unassisted  natural  selection  is 
not  to-day  considered  by  most  scientists  a  sufficient 
agent  for  producing  evolution.  But  everyone  con- 
nected with  the  subject  acknowledges  Darwin  as  the 
master,  and  says  that  it  was  his  work  which  con- 
verted the  w^orld  to  a  belief  in  evolution.  We  can 
have  no  better  preparation  for  an  intelligent  under- 
standing of  this  subject  than  to  consider  carefully  the 
life  of  this  remarkable  man  and  the  circumstances 
under  which  he  came  to  his  epoch-making  conclusions. 

Evolution  has  taught  us  to  attempt  as  far  as  may 
be  to  account  for  man  on  the  basis  of  his  heredity  or 
of  his  environment.  It  is  interesting  to  note  that  both 
of  these  factors  in  Darwin's  case  were  entirely  favor- 
able. In  the  latter  part  of  the  eighteenth  century 
Erasmus  Darwin  had  given  to  the  world  an  astonish- 
ing poem  in  which  he  anticipated  not  a  little  of  the 
thought  which  his  more  famous  grandson  was  to  make 
so  widely  known.  Josiah  Wedgwood  had  learned  to 
make  for  England  her  most  famous  pottery,  no  qual- 
ity of  which  was  more  widely  recognized  than  the 
sterling  patience  with  w^hich  it  was  made.  Erasmus 
Darwin,  with  his  scientific  proclivities,  and  Josiah 
Wedgwood,  with  his  sturdy  common  sense  and  pa- 
tient workmanship,  united  to  give  Charles  Darwin  his 


DARWIN    AND    WALLACE  23 

inherited  tastes,  for  he  was  a  grandson  of  both.  Born 
in  1809,  on  the  banks  of  the  Severn  in  England, 
Charles  Darwin  was  the  delicate  son  of  a  practicing 
physician  of  modest  but  sufficient  means.  Owing  to 
his  lack  of  early  vigor,  Darwin  spent  much  time  in 
the  open  air,  and  in  his  excursions  about  his  home  was  \ 
chiefly  interested  in  collecting  beetles.  This  taste, 
which  lasted  through  all  his  young  manhood,  is  the 
one  early  indication  of  the  traits  that  were  later  to 
develop.  At  first  in  the  day-school  and  later  in  the 
preparatory  school  Charles  Darwin  was  anything  but 
a  satisfactory  student.  Even  a  kindly  desire  later  to  ^ 
make  the  most  of  him  makes  it  impossible  to  find 
traces  of  any  especial  fondness  for  earnest  study. 
He  himself  believed  his  education  to  have  been  nearly 
useless,  although  he  doubtless  under-estimated  its 
value.  At  the  age  of  sixteen  he  went  to  Edinburgh 
at  his  father's  desire,  to  study  medicine.  The  sight 
of  the  dissecting-room  nauseated  him  completely,  and 
he  refused  to  continue  working  in  it.  Later  an  opera- 
tion which  he  witnessed  in  a  clinic  at  the  hospital 
sickened  him  so  thoroughly  that  he  declined  to  attend 
further  operations.  It  became  evident  that  the  young 
man  was  not  adapted  to  the  life  of  a  physician.  The 
next  move  was  to  educate  him  for  the  church,  and 
for  this  purpose,  at  the  age  of  nineteen,  he  went  to 
Cambridge.     Here  it  soon  appeared  that  he  was  no 


24  THE    MEANING   OF    EVOLUTION 

better  adapted  to  the  ministry  than  he  was  to  the 
practice  of  medicine,  and  his  university  career  went 
on  in  very  desultory  fashion.  Most  of  his  work  was 
distinctly  neglected,  ])ut  two  of  the  men  he  met  there 
were  to  influence  largely  his  future  life.  Henslow,  ^ 
the  botanist,  was  unusually  fond,  for  a  professor  in 
those  days,  of  work  in  the  field.  Charles  Darwin's 
tastes  coincided  with  those  of  Henslow,  with  whom 
he  formed  an  intimate  friendship.  He  was  always 
welcomed  as  a  companion  on  the  field  trips.  Though 
he  studied  little  of  botany  in  the  classroom  or  labora- 
tory, he  was  constantly  with  Henslow  or  with  Sedg- 
wick in  the  field.  Sedgwick  was  the  professor  of 
geology,  and  of  him  Darwin  was  particularly  fond, 
and  under  him  did  much  the  largest  amount  of  his 
study.  When  he  came  up  for  graduation  he  ranked 
tenth  of  those  who  "did  not  go  in  for  honors,"  a  not 
very  remarkable  class  standing.  He  was  still  required 
to  put  in  two  years  of  residence,  and  during  this  inter- 
val he  spent  most  of  his  time  with  Sedgwick  in  the 
study  of  geology  in  the  field.  Returning  to  his  home  ' 
after  a  geological  trip  into  Wales,  Darwin  found 
awaiting  him  a  letter  from  Henslow,  offering  him  an 
appointment  that  opened  to  his  ardent  mind  the  door 
to  a  career  after  his  own  heart. 

The  British  nation,  being  the  greatest  commercial 
nation  of  the  globe,  has  the  greatest  need  for  accurate 


DARWIN    AND    WALLACE  25 

charts  of  all  the  seas.  Frequently  she  has  sent  out 
great  charting  expeditions  to  various  parts  of  the 
world.  One  of  these  was  to  go  out  in  Her  Majesty's 
ship,  Beagle,  for  a  voyage  around  the  world.  Captain 
Fitzroy  was  in  command,  and  he  was  especially  com- 
missioned to  map  the  coast  of  South  America  from 
La  Plata  to  Cape  Horn  and  up  the  western  side.*^  In 
addition  to  this  work,  by  carrying  a  set  of  accurate 
chronometers,  he  was  to  check  up  the  longitude  of 
the  various  ports  to  be  visited  in  this  circumnaviga- 
tion of  the  globe.  It  was  customary  on  such  expe- 
ditions to  carry  a  young  man  whose  duty  it  was  to 
study  the  natural  history  of  the  countries  visited  on 
the  trip.  The  salary  of  such  a  naturalist  was  so  small 
that  an  experienced  man  could  scarcely  afford  to  take 
the  place.  Therefore  the  appointment  usually  went  to 
a  man  rather  of  promise  than  of  achievement. 
Through  Henslow's  influence,  Charles  Darwin  was 
offered  this  position  in  1831.  Darwin  hastened  to  ob- 
tain his  father's  permission,  but  the  elder  Darwin  at 
first  declined  to  consider  the  matter.  He  felt  that  his 
son  had  not  made  such  use  of  his  time  at  the  univer- 
sity as  warranted  the  hope  that  much  could  be  ex- 
pected of  such  a  journey.  He  believed  it  necessary 
that  Charles  should  have  some  means  of  earning  an 
adequate  living  before  he  could  think  of  devoting  his 
time  to  science.     Charles  found  an  efficient  advocate 


J 


26  THE    MEANING    OF    EVOLUTION 

ill  the  person  of  his  uncle,  Josiali  Wedgwood,  Jr. 
Together  they  persuaded  the  father  of  the  propriety 
of  giving-  to  Cliarles  this  opportunity  to  follow  out  his 
real  tastGs  and  ambitions.  Accordingly,  at  the  age  of 
twenty-two,  we  find  him  embarked  on  a  journey 
around  the  world.  In  the  cabin  of  the  Beagle  he  had 
abundant  time,  in  his  long  sail  across  the  Atlantic,  to 
read  the  two  volumes  of  Lyell's  ''Elements  of  Geol-  ^ 
ogy,"  which  Henslow  had  handed  him,  with  the  sug- 
gestion that  he  read  it,  but  on  no  account  believe  it. 
Filled  with  the  love  of  geology  as  Darwin  was,  this 
epoch-making  book  was  exactly  the  stimulus  needed. 
Lyell  had  just  begun  to  persuade  the  world  that  to 
understand  the  past  we  must  study  the  present.  In 
the  forces  now  at  work  he  saw  cause  enough  to  ac- 
count for  all  the  history  of  the  past  of  the  earth. 

There  is  little  doubt  that  this  book  was  one  of  the 
most  potent  factors  in  determining  the  bent  of  Dar- 
win's mind.  His  entire  educational  experience  had 
failed  to  appeal  to  him.  It  is  fortunate,  we  now 
know,  that  this  was  the  case.  If  the  university  course 
of  the  time  had  really  seized  him  it  would  have  made 
but  one  more  student  like  hundreds  it  was  turning  out 
each  year.  For  most  of  us  this  is  the  happy  event. 
Now  and  then  comes  the  rare  spirit  to  whom  all  of 
this  fails  to  appeal  because  he  is  ready  for  something 
better.     Such  was  the  spirit  of  Charles  Darwin.     He 


DARWIN    AND    WALLACE  2/ 

started  on  his  journey  with  a  mind  singularly  free 
from  prepossessions.  In  the  long-  hours  of  this  sail- 
ing voyage  across  the  Atlantic  Ocean  Darwin  had 
time  to  read  and  ponder  Lyell's  weighty  words.  By 
the  time  he  reached  the  Brazilian  shore  he  was  filled 
with  Lyell's  conception  that  the  present  is  the  child 
of  the  past,  developing  out  of  it  in  orderly  sequence. 
Lyell  expressly  denied  that  this  is  true  of  the  animal 
and  plant  world.  He  applied  it  only  to  the  face  of 
the  earth,  with  its  mountains  of  uplift  and  its  valleys 
of  erosion.  But  the  underlying  principle  of  an  or- 
derly development  under  the  action  of  natural  causes 
was  there.  In  Darwin's  mind  this  at  once  found  ac- 
ceptance, and  was  destined  to  a  fruition  its  author  had 
expressly  disclaimed. 

The  narrative  of  this  voyage,  as  subsequently  writ- 
ten, describes  the  islands  visited  by  the  Beagle  in 
crossing  the  Atlantic  Ocean.  The  contrast  between 
the  simple  and  general  interest  in  these  islands  and 
the  care  with  which  Darwin  described  the  Galapagos 
and  the  Keeling  Atoll  visited  later  in  the  voyage  are 
speaking  evidence  of  the  rapid  development  going  on 
in  the  mind  of  the  young  naturalist. 

Reaching  the  shore  of  South  America,  Darwin  first, 
turns  to  its  geology.     But  before  long  the  animal  life^ 
attracts  his  attention.     In  the  Brazilian  forest  Darwin 
had  his  first  experience  of  the  wealth  of  animal  and 


28  THE    MEANING    OF    EVOLUTION 

plant  life  in  the  tropics,  and,  like  all  naturalists,  he 
was  very  enthusiastic  over  it.  Among  the  animals 
that  particularly  attracted  his  attention  was  the  sloth, 
a  peculiar  creature  climbing  slowly  about  the  trees, 
small  of  size  and  sluggish  of  habit.  Another  animal 
that  interested  him  greatly  was  the  little  armadillo 
with  its  interesting  habit  of  curling  up  in  its  plated 
skin. 

Captain  Fitzroy  soon  finished  what  work  he  was 
required  to  do  in  this  neighborhood,  and  Darwin  was 
called  back  to  the  Beagle  to  continue  his  voyage. 
When  they  arrived  at  the  mouth  of  La  Plata  their 
most  serious  work  began.  Here  there  was  much 
tedious  charting  for  Fitzroy,  and  Darwin  could  now 
leave  the  vessel  for  a  lengthy  trip  on  shore.  This 
was  doubly  welcome.  Seasickness  was  nearly  constant 
with  Darwin  while  on  this  entire  voyage  and  every 
opportunity  to  work  on  land  was  eagerly  seized.  This 
region,  too,  was  rich  in  objects  of  interest  and  in 
strange  people.  While  exploring  the  pampas,  beyond 
Buenos  Ayres,  Darwin  came  across  the  skeletons  of 
the  great  mammals  some  of  which  Cuvier  had  pre- 
viously described.  He  studied  these  bones  with  much 
care,  and  recognized  at  once  in  the  megatherium  a 
great  similarity  in  structure  to  the  sloth  he  had  seen 
in  Brazil.  The  enormous  skeletons  of  the  glyptodons 
struck  him  also  as  strangely  similar  to  that  of  the  ar- 


^  , 


DARWIN   AND   WALLACE  29 

madillo.  One  evening,  seated  alone  in  the  broad 
expanse  of  the  pampas,  the  idea  suddenly  swept  over 
him,  stimulated,  of  course,  by  his  study  of  Lyell : 
"Can  it  be  that  the  little  armadillo  and  the  sloth  of 
to-day  are  the  degenerate  descendants  of  the  enormous  ^ 
megatherium  and  glyptodon  of  the  past?"  But  his 
mind  was  not  yet  ready  to  accept  so  bold  an  idea  and 
he  swept  it  aside. 

The  people  of  this  wild  neighborhood  interested 
Darwin  very  greatly,  and  he  describes  them  with  care. 
In  this  connection  a  charming  trait  of  Darwin's  char- 
acter comes  beautifully  in  evidence.  The  absolute 
purity  of  his  mind,  his  utter  freedom  from  grossness, 
shows  clearly  in  his  account  of  the  first  really  semi- 
civilized  people  he  had  ever  seen. 

A  little  later,  while  exploring  Patagonia,  Darwin 
noticed  the  terrace-like  formation  of  that  desolate 
country.  A  flat  near  the  sea  was  succeeded  by  a 
rapid  rise,  then  came  another  flat.  Three  of  these 
terraces  in  succession  stretch  back  toward  the  An- 
des. At  the  base  of  the  hi2:h  terraces  Darwin  found 
marine  shells,  largely  similar  to  those  of  the  ocean  ^ 
beach  so  many  miles  to  the  east.  His  study  of  Lycll 
led  him  to  suspect  at  once  that  this  portion  of  South 
America  had  been  raised  in  successive  stages  out  of 
the  bed  of  the  Pacific.  When  they  passed  around 
Cape  Horn  and  up  the  western  coast  he  hunted  for 


30  THE    MEANING    OF    EVOLUTION 

similar  beach  marks  on  the  sheer  western  face  of  the 
Ancles,  and  found  them  without  difficulty,  confirming 
his  idea  of  the  recent  rise  of  this  end  of  the  Andean 
chain. 

The  Beagle  continued  its  voyage  up  the  western 
coast  of  South  America  until  it  reached  Peru.  Once 
more  the  abundance  of  tropical  life  is  under  Darwin's 
eyes,  but  now  it  is  the  life  of  an  entirely  different 
section.  The  dry  climate  of  Peru  furnished  him  with 
an  environment  distinctly  unlike  that  of  the  moist  Bra- 
zilian forest.  He  collects  now  with  avidity,  gather- 
ing especially  insects  and  birds.  Then  the  ship  turned 
its  prow  westward  across  the  Pacific,  only  to  stop  five 
hundred  miles  out  at  the  Galapagos  Islands.  This 
little  group  he  studied  intensely,  collecting  large  num- 
bers of  insects  and  l)irds.  He  had  not  worked  over 
his  collection  long  before  he  realized  that  each  island 
in  the  group  had  peculiarities  which  marked  its  ani-\ 
mals  from  those  of  any  other  island.  Whenever  two 
islands  were  close  together  in  the  group  the  differ- 
ences in  their  fauna  were  found  to  be  comparatively 
slight.  If,  however,  he  examined  the  animals  from 
two  islands  lying  at  opposite  ends  of  the  group,  the 
differences  were  always  considerably  greater.  There 
was,  however,  a  strong  general  resemblance  among 
them  all  and  a  distant  though  not  so  strong  resem- 
blance to  the  corresponding  animals  of  the  Peruvian 


DARWIN    AND    WALLACE  3 1 

coast.  On  leaving  the  Galapagos  group,  Charles  Dar- 
win writes  in  his  diary  the  suggestive  observation 
that  this  little  group  of  rocky  islands  seems  to  be  one 
of  the  greatest  centers  of  creative  activity.  It  was 
this  interesting  resemblance  of  the  animals  of  these 
islands  to  each  other  and  to  those  of  the  Peruvian 
coast  that  finally  persuaded  Darwin  that  they  were 
all  related  and  were  all  descended  from  those  of  Peru. 
For  the  rest  of  his  life,  with  an  intensity  which  in- 
creased with  each  year,  Darwin  persisted  in  a  patient 
search  for  the  possible  agencies  by  which  such  change 
could  have  been  brought  about.  The  problem,  how- 
ever, was  temporarily  eclipsed  by  a  pressing  geological 
question  aroused  by  his  visit  to  the  Keeling  Atoll. 
Here  his  investigation  of  coral  reef  formation  abso- 
lutely captivated  him.  In  the  case  of  most  coral 
islands  in  the  Pacific  Ocean  the  reef  exists  as  a  circle 
of  coral  enclosing  a  lagoon  of  water.  In  the  center 
of  this  lagoon  stands  commonly  a  rocky  island.  It  is 
plain  that  this  is  the  foundation  on  which  the  coral 
built.  But,  in  the  case  of  the  Atoll,  the  coral  ring  was 
present  and  so  was  the  internal  lagoon,  but  there  was 
no  rocky  island.  The  key  to  the  solution  came  with 
an  interesting  discovery.  Darwin  began  to  put  down 
a  grappling'  iron  on  the  outer  side  of  the  reef  and 
to  drag  up  coral.  The  farther  away  from  the  reef  he 
went  the  deeper  was  the  water  from  whose  bottom  he 


22  THE    MEANING    OF    EVOLUTION 

pulled  the  coral,  \\liat  at  first  puzzled  him  was  the 
fact  that  so  long  as  he  dragged  up  his  coral  from 
depths  of  a  hundred  feet  or  less  the  coral  was  alive. 
Whenever  he  went  to  depths  of  much  more  than  a 
hundred  feet,  his  coral  was  always  dead,  though  he 
was  evidently  pulling  it  from  situations  in  which  it  had 
grown.  Then  Darwin  remembered  the  rising  Andes, 
lifting  themselves  out  of  the  bed  of  the  Pacific.  Here 
was  the  correlated  movement.  The  bottom  of  the 
ocean  here  was  sinking.  As  it  sank  it  dragged  down 
the  corals  with  it.  But  the  descent  was  so  slow  that 
new  corals  could  build  on  top  of  the  others  fast 
enough  to  keep  the  reef  up  to  the  surface  of  the  water. 
At  the  rate  of  growth  of  coral,  this  would  seem  to 
mean  that  the  bottom  could  be  sinking  at  a  rate  of 
only  a  few  feet  a  century.  But  while  the  reef  could 
keep  up  to  the  surface,  the  rocky  island  must  slowly 
sink.  Darwin  inferred  that  there  must  be  a  rocky 
summit  within  the  lagoon,  below  the  surface  of  the 
water.  A  little  sounding  soon  discovered  this  island, 
and  the  verification  of  Darwin^s  theory  of  coral  reef 
formation  was  at  hand.  The  description  of  this  Atoll 
and  of  his  theory  of  its  formation  won  for  Darwin 
the  esteem  of  geologists  when  he  later  presented  it 
in  book  form. 

The   voyage  was   continued   around   the   Cape   of 
Good   Hope.     Pursuing  the  usual  course  of  sailing 


DARWIN    AND   WALLACE 


33 


vessels,  the  Beagle  touched  once  more  at  Brazil,  re- 
turning home  to  England  in  1836,  after  an  absence  of 
five  years.  Charles  Darwin  himself  believed  this  trip 
to  have  been  both  his  education  and  his  opportunity. 
He  had  started  on  it  a  rather  careless  and  indifferent 
student.  He  returned  from  it  the  most  painstaking 
and  patient  naturalist  the  world  has  ever  known.  His 
father,  who  had  hardly  consented  to  his  going  because 
he  believed  him  not  stable  enough  to  be  intrusted  to 
his  own  devices  for  so  long  a  period,  was  profoundly 
moved  at  the  sight  of  him  on  his  return.  Believing 
in  phrenology,  as  did  many  of  the  physicians  of  his 
time,  his  father  turned  to  his  mother  and  said,  "Look 
at  the  shape  of  his  head ;  it  is  quite  altered" ;  which, 
translated  into  the  language  of  to-day,  would  read, 
"How  wonderfully  the  young  man  has  developed." 

A  part  of  Charles  Darwin's  duty  to  the  British 
Government  was  to  write  a  narrative  of  the  voyage, 
and  this  account  of  his  trip  upon  the  Beagle  is  one 
of  the  great  classics  of  travel  in  the  English  language. 
It  won  the  confidence  and  respect  of  a  wide  circle 
of  readers.  In  his  next  book  he  published  his  ob- 
servations made  at  the  Keeling  Atoll  and  announced 
his  theory  of  the  formation  of  coral  islands.  This 
was  a  distinctly  scientific  investigation,  and  it  won 
such  immediate  favor  among  geologists  as  to  increase 
materially  the  young  man's  reputation.    No  one  man 


34  THE    MEANING    OF    EVOLUTION 

is  ever  widely  enough  acqiiainlccl  with  the  animal 
world  to  classify  all  the  specimens  gathered  on  such 
an  expedition.  In  accordance  with  custom,  Darwin 
began  distributing  his  collections  among  specialists. 
Each  of  these  was  to  identify  and  describe,  to  name, 
if  necessary,  the  kind  of  material  he  knew  best. 
Among  others,  Darwin  had  a  considerable  collection 
of  barnacles  gathered  from  boats  and  wharves  in  all 
parts  of  the  world.  As  he  could  find  no  one  suffi- 
ciently acquainted  with  these  creatures  to  classify 
them  he  decided  reluctantly  to  work  them  up  him- 
self. For  about  eight  years  much  of  his  spare  time  was 
given  to  this  painfully  exacting  work.  He  expresses 
himself  as  fearing  it  was  a  waste  of  time.  Few  sys- 
tematic workers  will  agree  with  him.  He  did  his  work 
so  well  that  it  has  been  unnecessary  for  anyone  to  do 
it  again.  In  addition  it  gained  him  the  esteem  of  a 
new  circle  of  scientists  and  that  a  decidedly  exclusive 
circle. 

The  publication  of  these  books  did  much  for  Dar- 
win. His  narrative  of  the  voyage  gained  the  good 
will  of  cultured  England  in  general.  The  book  on 
coral  reefs  won  the  geologists.  His  "Manual  of  the 
Cirrhipedia"  (as  the  barnacle  book  was  called)  se- 
cured the  attention  of  systematic  zoologists.  The 
time  was  not  far  distant  when  he  would  need  every 
aid  possible  toward  gaining  and  keeping  the  regard 


DARWIN    AND    WALLACE  35 

of  men;  for  he  was  to  promulgate  a  theory  that  would 
arouse  the  bitterest  opposition  and  the  keenest  scorn. 
All  the  while  Darwin  was  working  on  these  books 
his  mind  was  quietly  busying  itself  with  what  he 
called  the  species  question.  The  more  he  studied  the 
material  collected  on  his  long  tour,  the  more  confident 
he  became  that  the  animals  of  the  present  are  the  7 
altered  descendants  of  the  animals  of  the  past.  He 
tried  patiently  to  work  out  every  conceivable  hypoth- 
esis to  see  whether  he  could  account  for  the  alteration. 
He  felt  quite  sure  animals  changed,  but  how  they 
changed,  and  why,  he  could  not  for  a  long  time  con- 
ceive. He  knew  that  gardeners  were  constantly  pro- 
ducing new  varieties  of  plants,  and  that  animals  of  va- 
rious breeds  were  clearly  the  descendants  of  other  and 
familiar  varieties.  Accordingly  he  began  to  study  the 
methods  of  animal  and  plant  breeders,  to  visit  their 
farms,  to  open  correspondence  with  them  and  read  all 
their  trade  journals,  to  undertake  experiments  in  the 
breeding  of  plants.  The  longer  he  worked  the  more 
confident  he  became  of  the  reality  of  the  change;  but 
for  a  long  time  no  glimmer  of  the  cause  by  which  it 
could  be  brought  about  came  to  his  mind.  In  1838 
he  came  across  a  book  by  Malthus  called  *'An  Essay  v 
on  Population,"  in  which  the  author  shows  that, 
whereas  man  increases  by  a  geometric  ratio,  he  can- 
not hope  to  increase  his  food  supply  in  more  than  an 


36  THE    MEANING   OF    EVOLUTION 

arithmetic  ratio.  That  is,  while  the  food  might  in- 
crease hke  the  series  2-4-6-8-10,  the  population  would 
increase  like  the  series  2-4-8-16-32.  On  this  basis  it 
is  only  a  (juestion  of  time  when  the  earth  will  be  too 
full  of  people  for  it  to  be  possible  for  the  food  to 
sustain  them.  Malthus  added  many  observations  and 
suggestions,  but  this  is  as  much  of  the  book  as  inter- 
ests us  in  this  connection.  Here  was  the  idea  that 
suggested  to  Darwin  his  agency  for  producing  the 
change  of  the  animals  of  the  past  into  those  of  the 
present. 

The  number  of  animals  of  any  particular  species  re- 
mains practically  the  same.  There  may  be  a  few 
more  one  year,  and  a  few  less  another,  but  on  the 
average,  year  by  year,  the  number  of  toads,  the  num- 
ber of  blacksnakes,  the  number  of  fieldmice,  remains 
sensibly  the  same.  Sometimes  the  rise  of  man  brings 
an  end  to  the  wild  population,  and  so  in  the  past  ani- 
mals have  dropped  out  of  the  race.  Yet  in  the  long 
run  and  for  a  considerable  time  the  number  of  any 
species  is  constant.  But  each  animal  produces  off- 
spring in  quantities  sufficient  to  far  more  than  replace 
himself  as  he  dies  out.  In  other  words,  animals  in- 
crease not  by  addition  but  by  multiplication.  Too 
many  are  born  for  all  of  them  to  live.  What  becomes 
of  the  great  mass  of  them?  The  answer  is  they  die; 
most  of  them  die  young.     Only  a  few  fortunate  in- 


DARWIN   AND   WALLACE  -t^J 

dividuals,  favored  by  being  a  little  stronger,  a  little 
more  cunning,  a  little  more  attractively  colored  than 
their  mates,  survive  to  carry  on  the  race. 

The  skillful  gardener,  looking  over  his  flowers,  finds 
a  ,plant  of  more  than  ordinary  beauty  and  thrift  of 
growth.  When  it  comes  to  maturity  he  keeps  its  seeds 
separate  from  those  of  the  rest  and  next  year  plants 
them  by  themselves.  As  they  come  up  he  weeds  out 
all  unthrifty  plants,  only  allowing  the  strongest  to 
come  to  maturity.  As  they  break  into  bloom  he  plucks 
away  all  whose  flowers  do  not  come  up  to  the  high 
standard  he  has  set  for  himself.  After  a  while  he 
has  but  a  few  plants  left,  but  these  are  the  thriftiest 
and  bear  the  most  beautiful  flowers.  Again  he  allows 
these  to  mature  and  selects  the  seed  of  the  very  finest. 
Next  year  the  process  is  repeated.  After  a  few  gen- 
erations, usually  three  if  the  man  is  skillful  enough, 
he  has  a  definite  strain  of  flowers  that  will  thereafter 
come  true.  This  is  the  process  of  artificial  selection 
as  carried  on  by  man. 

Darwin  saw  that  Nature  is  constantly  carrying  on 
a  similar  process.  She  produces  seeds  enough  on  al- 
most any  plant  to  clothe  the  world  in  a  few  years  if 
all  of  them  could  fall  into  proper  ground  and  thrive 
like  their  parents.  A  friend  of  mine  found  a  mullein 
stalk  that  bore  more  than  seven  hundred  seed  pods 
and  averaged  more  than  nine  hundred  seeds  to  the 


38  THE    MEANING    OF    EVOLUTION 

pud,  a  tutal  ui  more  than  six  hundred  and  thirty  thou- 
sand seeds.  If  each  of  these  could  find  lodgment  on 
a  plot  eighteen  inches  square,  produce  a  similar  num- 
ber of  seeds  and  plant  them  all,  the  result  would  be 
overwhelming.  The  fourth  generation  would  cover 
land  and  sea,  from  pole  to  pole,  one  hundred  layers 
deep.  But  there  is  no  such  danger.  Year  by  year 
the  mulleins  hold  their  own  and  no  more.  Any  par- 
ticular field  may  have  more  or  less,  but  in  the  long 
run  the  average  for  a  district  is  about  the  same.  Some 
of  the  seeds  are  poor  and  thin.  These  scarcely  sprout. 
Others  spring  up  into  thin-skinned  plants,  and  the 
first  frost  nips  them.  Still  others  lack  the  woolly 
coating  in  its  finest  abundance,  and  the  browsing  ani- 
mals eat  these.  Others  lack  power  to  put  out  a  wide- 
ranging  root  supply  and  the  first  drought  kills  these. 
Still  others  fail  to  send  up  a  vigorous  stem  and  the 
passing  animal  knocks  them  over  and  they  die.  Of 
the  few  that  are  still  surviving,  some  produce  such 
small  and  inconspicuous  blossoms  that  the  insects 
scarcely  see  them,  and  they  go  unfertilized.  In  the 
end  only  the  aristocrats  of  the  group  are  left,  aristo- 
crats in  the  best  sense  of  the  word.  These  are  strong, 
thrifty,  and  beautiful,  and  are  provided  with  every 
defense  known  to  the  mullein  world.  From  these  the 
mulleins  of  the  next  generation  will,  spring.  Again 
Nature  will  select  the  best  of  these,  by  a  repetition 


DARWIN    AND    WALLACE  39 

of  the  same  process.  Thus  year  by  year  the  stock  is 
improved.  Any  new  feature  that  is  favorable  helps 
its  possessor  to  survive,  and,  if  happily  mated,  will 
show  itself  after  a  while  in  the  entire  group.  This, 
in  brief,  is  the  underlying  idea  of  Natural  Selection,  i 
as  Darwin  conceived  it. 

In  1842,  at  Lyell's  suggestion,  Darwin  wrote  a 
short  sketch  of  his  ideas  which  he,  two  years  later, 
expanded  into  a  somewhat  larger  account.  The  manu- 
script of  these  early  views  of  the  theory  was  com- 
pletely lost  and  has  only  been  recovered  within  the 
last  few  years.  It  was  recently  published  under  the 
editorship  of  Charles  Darwin's  son,  Francis.  It  is 
astonishing  to  see  how  clearly  the  first  short  sketch 
states  the  underlying  conception  which  all  of  Dar- 
win's subsequent  work  amplifies.  Hooker  was  con- 
stantly urging  Darwin  to  write  out  his  whole  theory 
in  the  form  of  a  book,  and  Darwin  had  begun  to  do 
so  in  1856. 

Meanwhile,  down  in  the  Moluccas,  Alfred  Russell 
Wallace  had  been  lying  sick  of  a  fever  contracted 
during  his  exploring  expedition  in  that  neighborhood. 
He  had  been  studying  the  distribution  of  the  animal 
life  of  the  Malay  -Archipelago.  Overcome  by  sick- 
ness, as  he  lay  in  bed,  he  began  to  think  over  a  book 
which  he  had  read  not  long  before,  "Malthus  on  ' 
Population."      Wallace   had   been  pondering  on   the 


40  TTTE    MEANING    OF    EVOLUTION 

question  of  the  origin  of  the  animals  of  the  Malay 
Archipelago.     He  had  not  the  faintest  knowledge  of 
what  Darwin  was  doing,  but  was  inllucnced,  of  course, 
like  Darwin,  by  what  he  read  in  Malthus.    Interesting 
to  relate,  he  had  come  to  exactly  the  same  conclu- 
sions, writing  his  opinions  in  the  form  of  an  essay. 
By  the  strangest  sort  of  coincidence,  he  sent  this  essay 
to  Charles  Darwin,  asking  him  to  read  it,  and,  if  he\ 
thought  it  w^as  not  altogether  too  foolish,  to  send  it  ^ 
to  Lyell  for  publication  by  the  Linnoean  Society.    Dar- 
win  read  wath  utter  astonishment  this  essay  containing 
views  so  absolutely  like  those  that  had  come  to  him 
from  his  own  long  series  of  observations  and  reflec- 
tions.   With  uncommon  magnanimity  his  first  impulse 
was  to  withhold  his  own  publication  entirely,  but  to 
this  Lyell  and  Hooker  would  not  for  a  moment  con- 
sent.   They  were  determined  that  Darwin  should  give 
them  his  long  series  of  notebooks  as  evidence  of  the 
independence  of  his  work  and  that  he  present  to  the 
Linnaean  Society,  simultaneously  with  Wallace's  pa- 
per,   one   of   his    own   upon    the   same    subject.      In 
this  manly  form  both  essays  were  read  at  the  next 
meeting    of    the    society.      The    joint    papers    pro- 
voked   instant    discussion    and    prompt     opposition. 
The    world    at    large    scarcely    admitted     a    possi-    "* 
ble    doubt    of    the    fixity    of    species.      Men    gener- 
ally believed  the  idea  to  be  absolutely  irreconcilable 


■I 


DARWIN   AND   WALLACE  4 1 

with  their  reh'gious  faith.  Any  question  of  the  fact 
that  the  species  of  to-day  exist  practically  as  they  had 
been  handed  down  to  the  earth  in  the  beginning  by 
the  Creator  himself  seemed  to  most  men  a  direct  blow 
at  religion.  At  this  time  a  very  large  number  of 
natural  scientists  were  clergymen,  hence  the  opposi- 
tion had  abundant  and  influential  support.  The  storm 
grew  fiercer  and  more  widespread.  The  publication 
in  1859  of  Darwin's  great  book  on  *'The  Origin  of 
Species  by  Means  of  Natural  Selection  or  the  Preser- 
vation of  Favored  Races  in  the  Struggle  for  Life" 
added  fuel  to  the  flame. 

In  i860  the  British  Association  met  in  Oxford,  and 
Bishop  Wilberforce,  the  retiring  president,  in  accord- 
ance with  the  custom  of  the  society,  gave  a  summary 
of  the  advance  of  science,  especially  during  the  pre- 
ceding year.  Everyone  knew  perfectly  that  the 
bishop  would  deal  with  the  species  question,  and  that 
he  would  handle  it  severely.  Darwin  was  prevented 
by  his  usual  ill  health  from  being  present  at  this  meet- 
ing, but  Huxley  was  there  to  see  that  their  side  of 
the  question  received  proper  attention.  The  bishop 
made  a  lengthy  address,  in  the  major  portion  of 
which  he  brought  forward  entirely  worthy  objections 
to  Darwin's  theories.  Toward  its  close  his  feelings 
overmastered  him  and  he  departed  from  his  manu- 
script and  unburdened  his  mind.     The  lack  of  stenog- 


y 


42  THE    MEANING    OF    EVOLUTION 

raphers  in  those  days  and  the  tenseness  of  the  moment, 
wliich  made  everyone  forget  to  take  down  what  was 
said,  make  it  impossible  to  tell  exactly  what  happened. 
It  seems  that  Bishop  Will^erforce,  appealing  to  the 
prejudices  of  his  audience,  said,  in  language  that  now 
seems  ludicrous  but  then  was  terribly  bitter :  ''How- 
ever, any  of  us  might  be  willing  to  consider  ourselves  '^ 
descended  from  an  ape  upon  his  father's  side,  no  one 
v/ould  so  demean  his  mother's  memory  as  to  imagine 
that  she  could  possibly  have  shared  in  this  descent." 
Huxley,  who  had  w^aited  patiently  for  the  close  of  the 
bishop's  address,  saw  immediately  the  fatal  mistake. 
Turning  to  his  companion  beside  him,  he  said,  "The 
Lord  has  delivered  the  Philistine  into  my  hands,"  and, 
rising,  he  hurled  back  at  the  bishop  the  indignant 
reply,  'T  should  far  rather  owe  my  origin  to  an  ape 
than  I  would  owe  it  to  a  man  who  would  use  great 
gifts  to  obscure  the  truth."  The  bishop  had  made  the 
mistake,  and  the  struggle  was  on.  Year  by  year  it 
raged.  One  by  one  the  scientists,  first  of  England, 
and  then  of  Germany,  took  their  stand  by  Darwin. 
Huxley  in  England  and  Haeckel  in  Germany  were  the 
foremost  advocates  of  the  Darwinian  idea.  Long 
and  fiercely  the  battle  raged ;  slowly  and  gradually 
men  began  to  see  that,  instead  of  undermining  relig- 
ion, the  idea  of  evolution  uplifted  creation  and  made  it 
not  a  strange  happening  in  the  distant  past,  but  a 


J' 


DARWIN    AND    WALLACE  43 

divine  activity  through  all  time.  But  the  battle  had 
by  no  means  subsided  when  one  day  came  the  sad 
news  that  Darwin's  heart,  so  long  feeble,  so  serious  a 
hindrance  to  his  work,  had  beaten  its  last  on  April 
19,  1882. 

His  own  people  wished  to  bury  Darwin  quietly  at 
his  home  in  Down,  but  Darwin  now  belonged  to  the 
nation.  A  petition  signed  by  many  public  men  was 
sent  to  the  Dean  of  Westminster,  asking  that  his  body 
might  be  granted  burial  in  the  Abbey.  Probably  no 
greater  honor  can  come  to  man  to-day,  and  fortunately 
Dean  Bradbury  was  broad-minded  enough  to  acqui- 
esce. So  it  came  to  pass  that  the  church  that  had  so 
long  believed  him  her  enemy,  that  had  first  so  bitterly 
fought  him,  came  at  length  to  see  that  he  added  a 
new  dignity  and  worth  to  her  faith,  and  took  him  to 
her  bosom.     Darwin's  body  lies  buried  in  the  Abbey. 

In  all  the  glorious  company  of  immortal  dead  whose 
earthly  frames  are  gathered  in  England's  great  mauso- 
leum, there  is  no  other  one  who  has  done  so  much  to 
modify  the  mind  of  thinking  man. 


CHAPTER    III 

The  Underlying  Idea 

We  have  seen  in  the  preceding  chapters  how  the 
idea  of  evokition  worked  its  way  through  the  minds 
of  men.  Man  after  man  got  a  ghmpse  of  the  idea, 
even  among  the  ancient  philosophers.  But  no  one 
could  speak  convincingly  on  the  subject  before  modern 
times,  when  a  wider  acquaintance  with  the  animal 
world  gave  a  body  of  facts  on  which  it  was  safe  to 
base  conclusions.  Even  then  the  idea  eluded  men, 
until  there  came  a  worker  trained  by  a  long  voyage 
around  the  world  in  which  he  had  nothing  to  do  ex- 
cept to  study  nature.  He  finally  gathered  in  his  mind 
material  sufficient  to  convince  himself  not  only  of  the 
truth  of  evolution  but  of  the  process  by  which  this 
evolution  was  brought  about.  Every  scientific  prin-  ' 
ciple  is  simple  in  its  basal  idea.  In  actual  life  the 
action  of  the  principle  may  be  so  bound  up  with 
others  as  to  need  a  skillful  mind  for  its  detection.  But 
under  all  the  complexities  and  modifications,  like  a 
silver  thread  woven  into  a  cloth,  runs  the  basal  idea. 
Until  a  master  has  detected  it  the  presence  of  it  may 

44 


THE   UNDERLYING   IDEA  45 

be  unsuspected.  But  once  discovered  and  expounded, 
thereafter  anyone  may  follow  out  its  workings.  So 
it  is  with  the  Darwinian  idea  of  selection.  It  waited 
long  for  a  discoverer,  but,  once  found,  we  cannot 
but  wonder  why  men  did  not  see  it  earlier,  it  is  so 
simple. 

Mr.  Darwin's  mind,  while  slow  and  cautious,  had 
a  wonderful  perseverance.  When  he  had  finished  his 
work  he  had  not  only  given  a  clear  account  of  the 
process  of  evolution,  but  he  had  foreseen  almost  all  the 
valid  objections  that  were  afterward  to  be  brought  *^ 
against  his  theory.  Some  of  them  he  had  explained 
quite  fully;  of  others  he  indicated  a  possible  explana- 
tion; of  still  other  questions  he  confessed  that  as  yet 
they  were  not  plain.  But  the  whole  theory  is  so 
simple  in  its  fundamental  ideas  that  it  has  completely 
revolutionized  the  whole  aspect  of  modern  biology 
and,  indeed,  of  modern  thinking  in  many  lines. 

There  are  four  underlying  conceptions,  each  simple 
in  itself,  which  must  be  clearly  perceived  before  one 
can  understand  Mr.  Darwin's  theory  of  "Natural 
Selection."  The  first  of  these  is  known  under  the 
name  of  Heredity.  It  is  a  matter  of  common  ob- 
servation that  every  animal  or  plant  produces  offspring 
after  its  own  kind.  Under  no  conditions  would  we 
expect  a  duck  to  lay  an  egg  from  which  could  hatch 
anything  but  a  duck.      No   Plymouth  Rock  chicken 


46  THE    MEANING    OF    EVOLUTION 

mated  with  another  of  her  own  kind  will  ever  lay  an 
egg  that  will  produce  a  Rhode  Island  Red.  We  may 
believe  that  the  dog  has  descended  from  some  form 
of  wolf,  but  it  is  not  meant  that  at  any  particular 
time  in  the  past  any  wolf  mated  with  a  wolf  ever  pro- 
duced pups  that  were  anything  but  wolves. 

Why  this  should  be  so  is  one  of  the  most  profound 
problems  of  biology.  Nothing  but  the  fact  that  the 
process  has  gone  on  under  our  eyes  for  so  long  a  time 
could  blind  us  to  its  marvelous  character.  To  open 
the  Qgg  of  a  chicken  and  examine  it  by  the  most  re- 
fined methods  known  to  science  is  to  find  in  it  abso- 
lutely nothing  that  could  be  by  the  widest  stretch  of 
the  imagination  considered  anything  like  a  chicken. 
The  biologist  who  has  examined  such  eggs  before 
and  knows  them  in  all  stages  of  the  process  may  recog- 
nize in  an  egg  which  had  been  incubated  for  a  short 
time  something  which  his  previous  experience  tells 
him  will  become  a  chicken.  But  it  has  not  the  faint- 
est resemblance  to  a  chicken  until  later  in  its  develop- 
ment. In  early  spring  one  may  gather  pond  snails 
from  any  country  stream  and  place  them  in  an  aqua- 
rium. The  change  from  the  cold  water  on  the  out- 
side to  the  warmer  water  of  the  aquarium  and  the  tem- 
perate climate  of  the  room  hastens  the  process  which 
in  the  stream  would  not  take  place  until  later.  In  a 
short  time  one  may  fmd  fastened  to  the  glass  side  of 


THE    UNDERLYING   IDEA 


47 


the  aquarium  the  Httle  mass  of  transparent  jelly  which 
surrounds  and  protects  the  delicate  eggs  of  these  crea- 
tures. Fastened  as  they  are  it  is  easy  to  direct  a 
magnifying  glass  so  as  to  observe  the  change  which 
goes  on  within  these  transparent  eggs.  It  is  even 
possible  to  apply  a  microscope  in  such  a  way  as  to 
w^atch  the  transformation  under  the  low  power  of  the 
glass.  At  first  the  eggs  are  as  clear  as  water,  having 
at  the  center  a  slightly  yellowish  spot.  This  central 
mass  divides  and  subdivides  until  the  separated  sec- 
tions grow  so  small  and  numerous  as  to  lose  indi- 
viduality. Then  the  mass  begins  to  press  out  here 
and  dent  in  there.  After  a  little  while  a  double  line 
of  fine,  hairlike  projections  runs  around  the  creature. 
These  hairs  wave  in  such  fashion  as  to  make  the 
embryo  snail  revolve  slowly  in  its  Qgg.  A  little  later 
and  swellings  become  more  pronounced  over  the  sur- 
face. One  side  flattens ;  the  rotary  motion  stops ;  eyes 
appear  at  the  front  of  the  animal;  a  hump  on  the 
back  begins  to  be  covered  with  a  shell,  and  the  little 
creatures,  pushing  from  the  jelly,  start  their  life  jour- 
ney on  the  side  of  the  aquarium.  Why  did  it  happen? 
How  did  it  happen?  Here  we  have  seen  creation  at 
work.  Here  surely  the  hand  of  the  Creator  is  work- 
ing in  the  only  sense  in  which  the  Creator  may  be 
properly  said  to  have  a  hand.  How  the  history  of  the 
substance  out  of  which  the  egg  was  produced  provides 


48  THE    MEANING    OF    EVOLUTION 

for  the  future  development  of  that  egg  no  man  has 
yet  clearly  said.  This  is  not  to  say  that  we  shall 
never  know,  still  less  is  it  to  say  that  this  can  never 
be  known.  Ralph  Waldo  Emerson  has  said  that  there 
is  no  question  propounded  by  the  order  of  nature 
which  the  order  of  nature  will  not  at  some  time  solve. 
If  he  is  right,  and  I  believe  he  is,  we  shall  at  some 
time  know  how  it  is  that  this  egg  produces  this  snail. 
But,  as  I  said  before,  nothing  but  the  frequency  with 
which  the  process  goes  on  under  our  eyes  could  pos- 
sibly blind  us  to  the  marvel  of  it. 

The  regularity  with  which  each  animal  reproduces 
its  kind  is  no  more  surprising  than  the  faithfulness 
of  that  reproduction.  Some  of  our  birds  have  won- 
derful markings  on  their  plumage.  It  is  astonishing 
to  see  with  what  fidelity  the  feather  of  a  bird  may 
reproduce  the  corresponding  feather  of  its  parent.  It 
will  occur  to  everyone  how,  in  the  human  family  to 
which  he  belongs,  there  is  some  little  peculiarity  which, 
while  not  appearing  in  every  member  of  the  family, 
when  it  does  appear  is  remarkably  uniform.  It  may 
be  only  the  droop  of  an  eyelid,  it  may  be  a  tendency 
to  lift  one  side  of  the  lip  more  than  the  other,  it  may 
be  the  peculiar  shape  of  a  certain  tooth  in  the  set, 
and  yet  when  it  appears  it  comes  with  astonishing 
similarity  in  all  who  possess  it.  So  much  for  the 
principle  of  Heredity. 


THE   UNDERLYING   IDEA 


49 


The  second  great  underlying  idea  is  known  by  the 
name  of  Variation.  We  have  just  been  dwelling  on  / 
the  regularity  with  which  parents  produce  offspring 
like  themselves.  We  must  now  draw  attention  to  the 
fact  that,  while  it  is  true  animals  must  absolutely  be- 
long to  the  same  genus  or  species,  even  to  the  same 
variety,  none  the  less  no  animal  is  exactly  like  his 
parents.  Furthermore,  in  a  group  of  animals  pro- 
duced at  the  same  time  from  the  same  parent  each 
one  will  have  at  least  some  small  point  in  which  he 
differs  from  every  other  one  in  the  group.  Two  ani- 
mals may  look  alike  at  first  to  the  undiscerning  eye, 
but  a  keen  analysis  of  the  measurements  of  the  vari- 
ous parts  of  their  bodies  will  show  distinct  differ- 
ences. This  is  quite  as  true  among  lower  animals. 
A  toad  may  lay  a  double  string  of  four  hundred  eggs 
which  may  be  fertilized  by  the  same  male  at  the  same 
time.  These  eggs  may  develop  into  tadpoles  in  the 
same  pool  not  over  a  foot  square.  Within  a  few 
weeks  these  little  toads  may  have  gained  their  legs, 
lost  their  tails,  and  all  may  have  left  the  water  and 
taken  to  the  ground  upon  the  same  day.  Already  the 
careful  observer  will  notice  differences  among  them. 
Some  are  larger  than  others,  having  grown  more  rap- 
idly even  though  their  surroundings  were  exactly  the 
same ;  others  are  more  skillful  in  their  peculiar  method 
of  throwing  the  tongue  at  an  insect  they  wish  to  catch. 


50  THE    MEANING    OF    EVOLUTION 

Still  Others  will  be  differently  colored.  They  might  be 
arranged  to  show  a  considerable  gradation  between 
the  lightest  and  the  darkest  of  the  group,  though 
there  may  not  be  anywhere  in  the  row  a  considerable 
gap.  It  is  variation  in  animals  of  the  same  parentage 
and  same  surroundings  which  in  the  mind  of  Mr. 
Darwin  made  evolution  possible.  He  always  favored 
the  idea  that  it  was  the  continuous  accumulation  of 
these  small  variations  that  finally  produced  the  pro- 
found changes  which  mark  the  new  species.  He  ad- 
mitted the  possibility  of  the  occasional  appearance  of 
those  more  distinct  leaps  in  variation  on  which  the 
present  school  of  mutationists  so  strongly  insists;  but 
he  believed  them  to  be  less  influential,  in  the  general 
trend  of  evolution,  than  the  slower  but  much  more  fre- 
quent variations. 

One  of  the  most  complicated  and  perplexing  prob- 
lems in  the  biology  of  to-day  is  the  question  of  the 
origin  of  these  variations.  It  is  quite  as  hard  to 
understand  as  is  the  method  by  which  animals  pro- 
duce their  own  kind.  No  problem  is  being  more 
earnestly  studied.  Suppositions  we  have  in  consider- 
able number,  and  two  of  these  at  least  may  reasonably 
be  mentioned.  We  will  consider  first  the  less  certain 
theory.  There  is  nothing  in  the  Qgg  that  in  the  re- 
motest degree  resembles  its  parent.  The  old  idea  that 
every  acorn  had   in   it  a  miniature  oak   which  only 


THE    UNDERLYING    IDEA  5 1 

needed  to  unfold  itself,  or  that  the  hen's  egg  had 
within  it  a  miniature  chick  which  only  needed  the 
warming  process  in  order  to  make  it  evident,  could 
not  possibly  survive  the  invention  of  the  microscope. 
We  may  not,  and  we  certainly  do  not,  know  everything 
that  is  in  one  of  these  eggs,  but  we  do  know  most 
certainly  that  what  is  there  has  no  resemblance  to 
what  it  will  be  in  time.  The  biologist  finds  in  the 
nucleus  or  central  core  of  every  growing  and  repro- 
ducing cell  certain  minute  bodies  which  Weismann  be- 
lieves do  much  to  determine  the  growth  of  the  rest 
of  the  cell.  He  believes  also  that  there  are  many 
more  such  "determinants"  than  are  necessary  for  the 
reproduction  of  the  cell.  Each  of  these  determinants 
may  be  fitted  to  produce  slightly  different  results,  but 
what  decides  which  of  them  shall  have  its  own  way  is 
quite  uncertain.  It  may  be  that  one  determinant  hap- 
pens to  be  more  favorably  placed  than  others  in  the 
cell  and  that  it  has  consequently  secured  more  of  the 
nourishment  that  comes  to  the  cell  in  the  blood  of  its 
parent.  If  this  is  true  it  would  certainly  be  favored 
in  the  competition.  We  are  becoming  quite  certain 
that  whatever  variations  arise  really  start  in  the  egg. 
The  simplest  conception  as  to  the  cause  of  variation 
would  seem  to  be  varied  experience.  One  man  trains 
his  brain,  another  his  hand ;  and  in  each  case  the  organ 
so  trained  develops.     But  science  is  strongly  of  the 


52  THE    MEANING    OF    EVOLUTION 

mind  that  such  influence  does  not  reach  the  next  gen- 
eration. 

A  musician  may  have  taught  his  fnigers  to  be 
nimble;  may  have  given  them  speed  of  motion  and 
precision  in  their  action.  No  child  of  his  born  after 
he  acquired  this  wonderful  facility  of  execution  is 
any  more  likely  to  be  a  skilled  musician  than  a  child 
born  before  he  had  ever  practiced  enough  to  be  any- 
thing more  than  a  crude  performer.  Science  is  nearly 
certain  that  his  children  are  just  as  likely  to  be  tal- 
ented along  musical  lines  if  he  himself  never  had  be- 
come a  musician,  simply  because  he  had  it  in  him 
to  be  a  musician;  In  other  words,  they  may  inherit 
the  talent  which  he  developed,  but  they  inherited  it 
not  because  he  developed  it,  but  because  it  was  in 
him  to  be  developed.  This  is  in  accordance  with  the 
famous  principle  that  there  is  no  inheritance  of  ac- 
quired characters.  We  shall  touch  this  question  a 
little  more  fully  in  a  later  chapter,  in  speaking  of  the 
development  of  the  evolution  theory  since  Darwin's 
time. 

If  we  are  right  in  this  matter,  and  we  certainly  are 
nearly  right,  variation  must  take  place  for  the  most 
part  in  the  germ.  These  variations  may  not  show 
until  the  animal  has  grown  up,  but  they  must  have 
taken  place  among  the  determinants  in  the  germ  cell 
or  they  would  not  reappear  in  subsequent  generations. 


THE    UNDERLYING?   IDEA  53 

There  is  another  process  by  which  new  variations 
may  arise  and  which  is  more  easily  understood.  It 
is  the  method  of  double  parentage.  The  Barred 
Plymouth  Rock  chicken  had  its  origin  in  such  a 
double  ancestry.  The  one  parent  was  a  Black  Java 
whose  color  has  disappeared  entirely  in  the  cross,  but 
whose  single  comb  with  its  few  large  points  comes  out 
clearly  in  the  newly  produced  fowl.  The  other  parent 
was  a  Barred  Dominique.  It  is  to  this  parent  that 
the  Plymouth  Rock  owes  the  interesting  cross  mark- 
ings on  its  feathers.  The  comb  on  the  head  of  the 
Barred  Dominique  is  of  the  type  known  as  the  rose- 
comb,  having  many  rows  of  slight  projections.  This 
has  completely  disappeared  from  the  Plymouth  Rock 
fowls.  I  am  told  that  the  skilled  chicken  fancier  can 
tell,  concerning  many  points  in  this  fowl,  to  which  of 
the  crossed  ancestors  each  quality  is  due.  To  a  cer- 
tain extent  it  is  undoubtedly  true  that  here  we  have 
the  secret  of  the  origin  of  many  of  those  interesting 
people  whom  we  are  pleased  to  call  geniuses.  They 
may  not  possess  any  qualities  not  clearly  discernible 
in  various  of  their  near  ancestors,  but  in  them  we  find 
what  w^e,  for  the  lack  of  a  better  understanding,  call 
chance  combination  in  one  individual  of  the  finer  quali- 
ties of  many  ancestors,  and  this  individual  is  so  placed 
in  life  as  to  have  these  qualities  developed  and 
strengthened. 


54  THE    MEANING    OF    EV^OLUTION 

Charles  Darwin,  humanly  speaking,  may  be  ac- 
counted for  as  the  happy  combination  of  a  double 
heredity  and  a  favorable  environment.  He  inherited 
the  scientific  inclinations  of  his  grandfather,  Erasmus 
Darwin,  and  the  patient,  sturdy  honesty  of  his.  other 
grandfather,  Josiah  Wedgwood.  These  developed 
under  the  stimulus  of  the  long  five-year  voyage,  face 
to  face  with  the  world  of  nature.  This  happy  com-  i 
plex  produced  the  master  biologist.  To  believe  that 
he  came  about  purely  by  chance  requires  a  great 
stretch  of  the  imagination.  ^'There's  a  divinity  that 
shapes  our  ends." 

We  have  endeavored  to  make  clear  two  of  the  basal 
ideas  underlying  evolution.  One  of  these  is  respon- 
sible for  the  continued  production  of  animals  or  plants 
of  the  same  kind,  preventing  the  world  from  becom- 
ing a  wild  kaleidoscopic  and  fantastic  dream.  Hered- 
ity is  the  conservative  force  of  nature.  The  other  idea 
underlies  the  development  of  new  departures  which 
keep  the  world  from  being  a  dull,  dead,  unending 
repetition  of  the  same  monotonous  material.  Varia- 
tion is  the  progressive  tendency  in  nature. 

The  third  basal  idea  is  that  of  Multiplication.  Ani- 
mals and  plants  multiply ;  they  do  not  simply  increase, 
they  increase  in  a  geometrical  ratio.  Anyone  who 
has  worked  out  one  of  these  geometrical  ratios  knows 
how  wondrously  they  mount  up.     There  is  an  old  fa- 


THE    UNDERLYING    IDEA 


55 


miliar  story  of  the  blacksmith  who  asked  the  price  at 
which  the  stranger  would  sell  the  horse  he  was  shoe- 
ing. The  owner  of  the  horse  replied  that,  if  the  black- 
smith would  give  him  one  penny  for  the  first  nail  he 
drove  into  the  shoe,  two  for  the  second,  four  for  the 
third,  and  so  on,  he  might  have  the  horse.  No  hun- 
dred horses  in  the  world  taken  together  have  ever 
brought  such  a  price  as  the  blacksmith  would  have 
had  to  pay  for  the  animal  on  which  he  was  working. 
This  is  no  circumstance  to  the  awful  story  of  what 
would  happen  to  the  earth  if  any  animal  could  multi- 
ply unrestricted.  The  usual  number  of  eggs  laid  by 
a  mother  robin  for  a  single  brood  is  four,  and  she  may 
produce  two  broods  in  one  season.  This  would  mean 
that  the  original  pair  had  produced  eight  offspring, 
four  times  their  own  number.  If  we  can  imagine 
these  mating  the  next  year  and  producing  their  kind 
in  the  same  proportion;  and,  if  we  further  suppose 
that  each  robin  needs  a  space  one  hundred  feet  square 
from  which  to  gather  his  food,  we  realize  the  aston- 
ishing fact  that  in  fifteen  years  every  patch  one  hun- 
dred feet  square  in  Pennsylvania  and  New  York  would 
each  have  its  resident  robin,  while  the  following  sea- 
son would  find  a  robin  on  every  similar  patch  from 
Maine  to  the  Carolinas.  Of  course  this  could  never 
happen,  this  is  simply  what  would  happen  if  all  the 
robins  could  grow  to  maturity  and  reproduce  at  the 


56  THE    MEANING    OF    EVOLUTION 

normal  ratio.  But  the  robin  is  a  comparatively  slow 
producer. 

Our  turtles  are  more  prolific.  Twenty  eggs  would 
probably  not  be  an  unusual  number.  If  we  could  im- 
agine a  turtle  to  live  in  the  sea  and  to  produce  at  this 
rate;  and,  if  each  turtle  should  need  as  much  room 
each  way  as  the  robin,  and  a  depth  of  water  equal 
to  its  width,  before  the  robins  had  spread  over  New 
York  and  Pennsylvania  the  turtles  would  have  filled 
all  the  seas  of  the  globe.  Frogs  are  even  more  re- 
markable in  this  respect.  Two  hundred  eggs  is  not 
an  uncommon  number.  If  each  frog  required  a  space 
twenty-five  feet  square  on  which  to  subsist,  the  entire 
earth  would  be  more  than  covered  with  them  within 
six  years.  It  is  ludicrous  to  think  of  such  numbers, 
especially  when  we  realize  the  hundreds  of  thousands 
of  kinds  of  animals  there  are  in  the  world,  each  of 
which  is  also  multiplying,  and  it  becomes  evident  at 
once  that  only  an  infinitely  small  proportion  of  all 
these  creatures  can  possibly  survive.  This,  then,  is 
multiplication. 

Here  comes  into  play  the  fourth  basal  idea  in  Mr. 
Darwin's  explanation.  This  is  the  part  of  Selection. 
When  man  produces  new  varieties  of  animals  he  does 
it  by  picking  out  from  his  flocks  or  his  herds  such  as 
conform  most  nearly  to  his  idea  of  what  is  desirable. 
These  he  mates,  and  from  their  progeny  he  selects 


THE    UNDERLYING   IDEA  57 

the  ones  that  suit  him  best.  Generation  by  generation 
he  gets  his  domesticated  animals  to  conform  more 
nearly  to  the  standard  of  his  desires.  Natural  selec- 
tion works  in  exactly  similar  fashion.  Of  all  the 
eggs  that  are  produced  by  the  animals  at  large  in 
nature  an  overwhelming  proportion  never  develop  at 
all.  They  dry  up,  are  eaten  by  their  enemies,  find 
no  suitable  place  or  time  for  development  and  decay, 
or  are  overtaken  by  some  other  calamity.  Of  the 
animals  which  emerge  from  the  remainder  an  over- 
whelming majority  come  to  an  untimely  end  within 
the  first  few  days  of  life.  Each  has  countless  enemies 
which  prey  upon  him,  and  these  have  scarcely  de- 
voured him  before  they  themselves  become  the  prey 
of  some  stronger  creature.  Until  Mr.  Darwin  gave 
us  his  elemental  idea  it  was  taken  for  granted  that 
it  was  a  matter  of  pure  accident  which  survived  and 
which  yielded  in  the  struggle  and  cares  of  life.  It 
was  Darwin  who  showed  us  that  in  this  tremendous 
struggle  against  those  of  his  own  kind  in  the  search 
for  the  same  food,  against  the  elements,  in  securing 
a  mate,  any  animals  possessing  a  superiority,  however 
slight,  must  have  some  little  advantage  in  the  battle. 
Certainly,  where  so  many  must  utterly  fail,  only  those 
could  possibly  succeed  who  were  well  fitted  to  the 
circumstances  in  which  they  must  live.  We  used  to 
think  animals  were  destroyed  by  the  "accidents"  of 


58  THE    MEANING    OF    EVOLUTION 

life  and  no  one  could  foretell  accidents.  Mr.  Dar- 
win made  clear  that  it  was  not  a  question  of  chance. 
That  Vvhich  might  happen  to  any  individual  animal 
might  be  what  we,  not  knowing"  the  process,  called 
accident,  and  yet  there  could  be  no  possible  doubt 
that  those  who  succeeded  were  better  fitted  to  battle 
with  life  than  those  who  failed,  and  that  their  suc- 
cess was  due  primarily  to  their  being-  thus  advantaged. 
Consequently,  if  g'eneration  by  generation  the  so-called 
accidents  of  life  are  constantly  eliminating-  the  unfit 
in  overwhelming  proportions,  not  only  must  the  posi- 
tively unfit  disappear,  but  even  the  less  fit.  The  more 
keen  the  struggle,  the  fewer  could  survive  and  the 
fitter  they  must  be  to  survive  at  all.  This  is  Selec- 
tion. These,  then,  are  Darwin's  four  great  factors! 
of  evolution :  Heredity,  Variation,  Multiplication,  Se-^ 
lection.  / 

From  these  it  results  that  the  animals  and  plants 
naturally  become  better  adapted  to  the  situation  in 
which  they  are  placed.  W^hen,  as  is  constantly  hap- 
pening- through  the  history  of  the  earth,  a  chang-e  oc- 
curs in  the  physical  geography  of  any  region,  wdien 
a  plain  is  lifted  to  be  a  plateau,  or  a  mountain  chain 
is  submerged  until  it  becomes  a  row  of  small  islands, 
this  alteration  will  produce  uncommon  hardships 
among  animals,  even  though  they  were  w^ell  fitted  to 
the   old   conditions.      Any  animal  or  any  species  of 


V  I 


THE    UNDERLYING    IDEA 


59^ 


animals  which  meets  such  a  calamity  has  before  it 
only  three  possible  outcomes  of  the  struggle.  First 
it  may  be  plastic  enough  and  it  may  vary  enough  in 
the  right  direction  to  adjust  itself  to  the  changed  con- 
ditions. In  this  case  it  and  a  favored  few  like  it 
will  occupy  the  altered  territory.  The  second  possi- 
bility is  that  it  may  migrate  while  the  actual  change  is 
going  on,  thus  remaining  in  the  sort  of  situation 
suited  to  it  and  its  kind.  The  third  possibility  is  the 
one  which  overtakes  a  great  majority  of  animals — 
they  die.  Even  the  entire  line  dies  out,  and  the  strata 
of  the  rocks  are  filled  with  the  bones,  shells,  and  teeth 
of  such  as  have  met  this  fate.  They  have  become 
extinct. 

Thus  far  in  this  chapter  we  have  been  considering 
the  influences  under  which  it  is  conceivable  that  ani- 
mals should  advance.  There  is  no  question  whatever 
that  there  are  too  many  animals  born,  nor  is  there  any 
possible  question  that  a  very  large  proportion  of  them 
must  certainly  die.  There  is  equally  no  doubt  that 
every  animal  produces  after  its  own  kind,  and  that  its 
offspring,  while  they  resemble  it  closely,  still  vary  a 
little  from  it  and  from  each  other.  This  fact  is  per- 
fectly plain  to  the  most  superficial  observer  who 
thinks  on  the  matter  at  all.  It  is  not  so  plain,  nor  is 
it  easily  demonstrated,  that  all  of  these  acting  to- 
gether do  surely,  even  if  slowly,  alter  the  form  and 


6o  THE    MEANING    OF    EVOLUTION 

behavior  of  the  animal  world.  Tt  is  difficult  to  prove 
that  there  is  going  on  under  our  eyes  a  steady  and 
real  improvement  in  the  adaptation  of  the  animals  and 
plants  around  us  to  the  situation  in  which  they  are 
placed.  As  far  back  as  man's  memory  runs  they 
seem  to  have  been  about  what  they  now  are;  as  far 
even  as  man's  historical  record  runs  they  seem  to  have 
suffered  no  great  alteration.  The  Egyptian  of  the  old 
tombs  is  much  like  the  Egyptian  of  the  same  rank 
to-day.  The  African  of  the  tombs  has  the  African 
features  of  to-day.  Under  such  circumstances  it  is 
hard  to  prove  that  there  is  a  steady  and  undoubted 
advance.  For  the  most  part  the  balance  of  the  ani- 
mal world  is  fairly  even,  and  any  species  does  not 
ordinarily  change  rapidly  enough  or  migrate  widely 
enough  to  show  us  its  new  features.  It  is  difficult  to 
see  the  struggle  w^hich  we  are  so  sure  is  going  on. 
The  life  of  animals  is  so  hidden  in  many  of  its  de- 
tails that  their  joys  and  sorrows,  if  such  we  may  call 
them,  scarcely  fall  under  our  observation.  Now  and 
then  an  opportunity  comes  to  see  the  process  of  adap- 
tation work  itself  out.  The  struggle  for  existence  be- 
gins anew  and  is  carried  on  with  special  vigor,  with 
victory,  temporary  or  permanent,  to  one  of  the  par- 
ticipants in  the  struggle. 

The  opportunity  to  observe  such  a  change  is  pre- 
sented in  the  United  States  by  the  introduction  of  the 


THE   UNDERLYING   IDEA  6l 

so-called  English  sparrow.  This  little  creature,  re- 
ceived at  first  with  such  joy,  soon  became  the  object 
of  an  almost  bitter  hatred  on  the  part  of  very  many 
people.  This  is  really  due  to  the  fact  that  this  bird  is 
one  of  nature's  darlings  and  thoroughly  succeeds 
where  it  has  an  even  chance. 

The  number  of  birds  of  any  particular  species  which 
a  region  will  support  seems  to  be  fairly  definite.  If  a 
species  is  especially  protected  until  it  becomes  unusu- 
ally abundant,  the  removal  of  the  protection  commonly 
brings  it  down  promptly  to  its  original  numbers.  On 
the  other  hand,  an  accident  of  severe  character  or  a 
special  persecution  may  much  diminish  the  number  of 
the  species,  and  still  it  will,  within  a  comparatively 
few  years,  return  to  its  previous  abundance. 

The  inhabitants  of  Florida  who  own  orange  groves 
will  never  forget  the  winter  of  '94-5.  A  bitter  cold 
wave  swept  along  the  coast  and  killed  such  large  num- 
bers of  orange  trees  as  almost  to  cut  Florida  out  of  the 
orange  market  and  to  open  the  gate  to  California, 
who  was  eagerly  offering  her  fruit.  This  same  frost 
caught  the  migrating  blue  birds  and  killed  them  by  the 
thousands.  When  spring  came  bird-lovers  throughout 
the  eastern  United  States  found  an  astonishing  scar- 
city of  these  favorites.  It  was  feared  that  with  num- 
bers so  small  they  could  not  possibly  compete  with 
their  enemies  and  with  whatever  untoward  circum- 


62  THE    MEANING    OF    EVOLUTION 

stances  should  be  their  lot.  But  there  is  room  in  this 
environment  for  a  definite  number  of  bluel)irds.  When 
this  number  was  suddenly  reduced  the  chances  to  make 
a  bluebird's  living  were  so  wondrously  multiplied  that 
young  bluebirds  had  such  an  opportunity  in  life  as 
their  fellows  had  not  had  for  many  long  years.  Ac- 
cordingly they  thrived  as  never  before,  and,  of  their 
progeny,  a  larger  proportion  lived  to  the  following 
year.  It  was  only  a  few  years  before  the  number  of 
bluebirds  had  risen.  Now  we  probably  have  as  many 
as  we  have  had  for  a  long  time  past.  I  cite  this 
simply  to  show  that  a  region  can  support  a  certain 
number  of  animals  of  any  one  particular  kind,  and 
that  the  animal  is  likely  to  multiply,  if  given  a  fair 
chance,  until  it  has  reached  such  proportions.  Now  to 
my  story  of  the  rapid  development  of  a  newcomer. 

In  the  year  1850  a  resident  of  Brooklyn  came  home 
from  a  trip  to  Europe.  He  was  a  lover  of  birds,  and 
while  in  Europe  had  been  particularly  attracted,  no  one 
now  knows  quite  why,  to  the  common  House  Sparrow, 
as  it  should  be  called.  It  is  no  more  abundant  in 
England  than  in  many  parts  of  the  continent  of  Eu- 
rope. A  name  that  has  been  used  for  a  long  time  is 
very  hard  to  cast  aside,  and  we  shall  probably  con- 
tinue to  mistakenly  call  him  the  English  Sparrow  to 
the  end.  Our  Brooklyn  traveler  brought  home  with 
him  from  Europe  eight  of  these  interesting  little  birds 


THE    UNDERLYING    IDEA  63 

and  succeeded  in  inducing  his  colleagues  in  a  scientific 
society  to  share  his  interest  in  them.  Not  wishing  to 
commit  the  newcomers  suddenly  to  the  rigors  of  the 
American  winter,  these  men  built  a  large  cage  for  the 
sparrows,  meaning  to  set  them  free  in  the  spring.  For 
some  reason  or  other  when  the  winter  was  over  the 
birds  were  all  dead,  and  this  first  attempt  to  introduce 
the  sparrow  into  America  failed  entirely.  The  little 
bird  had  won  so  many  friends  that  his  success  was 
now  sure.  Finding  a  favorable  opportunity,  these 
Brooklyn  men  dispatched  an  order  to  a  man  in  Eu- 
rope, asking  him  to  supply  them  with  one  hundred 
English  sparrows.  The  consignment  came  in  good 
shape  and  the  birds  were  liberated  on  the  edge  of 
Brooklyn.  This  was  the  first  of  a  number  of  intro- 
ductions. A  little  later  New  York  City  sent  for  two 
hundred  and  twenty  of  these  interesting  creatures  and 
turned  them  loose  in  her  parks,  while  Rochester,  with 
what  was  then  considered  great  public  spirit,  pur- 
chased one  hundred  for  herself.  But  the  most  pro- 
gressive city  in  this  respect  was  Philadelphia.  She 
had  long  been  troubled  with  the  spanworm  on  h^r 
trees.  This  detestable  larva  had  the  unpleasant  fash- 
ion of  lowering  itself  by  a  long  silken  thread  from 
the  shade  trees  then  so  abundant  in  that  beautiful  city. 
The  spanworms  traveling  around  over  the  clothing  of 
the  passersby  were  so  objectionable  to  everybody  that 


64  THE    MEANING    OF    EVOLUTION 

it  was  with  greatest  delight  that  Philadelphia  heard  of 
the  new  birds  which  ate  the  pest.  One  wonders  why 
some  ornithologist  did  not  look  at  the  bird  long 
enough  to  see  that  it  had  the  sort  of  a  bill  character- 
istic of  birds  that  eat  seeds.  It  is  true  that  most  birds 
feed  their  young  on  insects,  hence  there  is  a  time  when 
any  bird  is  apt  to  be  insectivorous.  But  the  structure 
of  the  sparrow's  bill,  like  that  of  all  finches,  should 
have  warned  these  bird-lovers  that  the  sparrow  was 
not  to  be  depended  upon  to  earn  his  living  by  catching 
worms.  It  is  easy,  however,  to  be  wise  after  the 
event.  Philadelphia  believed  she  was  engaging  in  a 
particularly  advanced  movement  wdien  she  imported 
from  England  one  thousand  English  sparrows,  nearly 
as  many  as  were  liberated  by  all  other  cities  together. 
These  birds  were  turned  loose  among  the  shady  streets 
and  wide  spreading  parks  of  the  City  of  Brotherly 
Love. 

It  is  a  serious  matter  lightly  to  disturb  the  balance 
of  nature  by  the  introduction  of  a  new  species.  It  is 
true  that  the  sparrow  did  eat  some  spanworms  and 
for  a  while  enthusiastic  bird-lovers  hoped  that  here 
was  the  solution  of  the  difficulty.  Philadelphians  will 
also  remember  that,  with  the  spanworm  removed  from 
competition,  the  tussock  moth,  whose  caterpillar  car- 
ries on  his  back  a  series  of  yellow,  red,  and  black 
paint  brushes,  at  once  become  the  permanent  parasite 


THE    UNDERLYING   IDEA  65 

of  the  long-suffering  shade  trees.  This  caterpillar  is 
covered  with  bristling  hairs,  very  closely  set.  Almost 
any  bird  objects  to  hair  in  his  victuals;  and  this  par- 
ticular larva  has  hair  more  than  ordinarily  objection- 
able, for  it  irritates  wherever  it  pricks  the  sensitive 
skin.  This  coating  seems  to  protect  the  caterpillar 
from  the  sparrow,  with  the  result  that  Philadelphia's 
trees  were  soon  nearly  defoliated  by  this  comparatively 
new  pest,  worse  than  the  spanworm.  With  the  pav- 
ing of  the  city's  highways  and  the  consequent  shut- 
ting off  of  the  air  from  the  roots,  the  trees  have 
largely  disappeared  from  the  streets  of  Philadelphia. 
With  them  have  gone  a  fair  portion  of  the  tussock 
worms,  but  the  sparrow  holds  his  own.  Here  is  a  new 
bird  in  the  field,  and  the  struggle  for  existence  on 
the  part  of  every  other  kind  of  bird  is  now  more  com- 
plicated and  severe.  The  sparrow  can  live  where  the 
rest  of  the  birds  have  no  possible  chance.  He  throve 
so  well  in  this  country  that  by  1875  he  had  spread 
over  five  hundred  square  miles  in  the  neighborhood 
of  our  larger  Eastern  cities.  Thus  far  almost  every- 
body was  pleased  with  the  new  introduction.  Within 
the  next  five  years  he  had  spread  over  more  than  fifteen 
thousand  square  miles,  and  wise  men  were  beginning 
to  feel  doubtful  of  the  virtues  of  their  aforetime 
friend.  When  by  1885  more  than  five  hundred  thou- 
sand square  miles  had  been  occupied  by  the  enterpris- 


66  THE    MEANING   OF    EVOLUTION 

ing"  little  fellow,  there  remained  no  longer  a  doubt  in 
the  minds  of  most  people  that  the  sparrow  was  an 
unmitigated  nuisance  and  great  fears  were  entertained 
that  he  had  multiplied  to  such  an  extent  as  to  be  a 
serious  menace.  Here,  then,  is  a  modern  instance 
under  our  own  eyes  of  a  victory  in  the  struggle.  If 
the  sparrow  has  multiplied  rapidly,  while  all  the  other 
birds  have  either  only  held  their  own  or  even  have 
diminished  in  numbers,  it  is  quite  evident  he  must  be 
better  fitted  to  the  conditions  than  they  are.  What 
are  his  fit  points?  Why  does  he  succeed  while  others 
fail?  The  thoughtful  bird-lover  will  have  little  trouble 
in  understanding  at  least  some  of  his  victory-winning 
characteristics.  How  did  he  come  to  be  almost  the 
only  bird  who  can  live  in  large  numl)ers  in  our  great 
cities,  without  losing  his  ability  to  get  along  in  less 
crowded  situations  ? 

In  the  first  place  this  interesting  bird  is  a  clannish 
fellow.  He  has  lost  the  ordinary  sparrow  habit  and 
has  come  to  like  to  live  in  crowded  groups.  Seclu- 
sion is  not  at  all  to  his  taste,  and  if  there  are  only  a 
few  sparrows  in  the  neighborhood  those  few  will  most 
certainly  be  found  living  near  each  other.  One  of  the 
early  adaptations  of  the  sparrow  to  his  city  surround- 
ings was  the  ability  to  find  for  himself  a  considerable 
proportion  of  his  food  in  the  undigested  seed  that 
could  be  picked  up  from  the  droppings  of  the  horses. 


THE    UNDERLYING    IDEA  67 

This  naturally  led  the  surplus  sparrows  out  through 
the  many  thoroughfares  leading  from  any  large  city. 
Where  horses  went  sparrows  could  follow.  Accord- 
ingly along  the  great  lines  of  travel  this  bird  found 
the  simple  path  by  which  he  could  enter  new  territory. 
Meanwhile  box-cars  came  into  our  large  cities  with 
freight.  Sometimes  they  had  carried  grain,  sometimes 
cattle.  In  either  case  it  was  not  unlikely  that  a  cer- 
tain amount  of  grain  should  be  found  scattered  over 
the  floor  of  such  cars.  The  sparrow  visited  these  cars 
for  the  grain,  and  it  must  have  been  no  infrequent 
accident  that  a  door  should  be  shut  upon  a  group  of 
sparrows,  especially  in  inclement  weather,  when  they 
were  apt  to  be  huddled  in  a  dark  corner  of  the  car. 
These  prisoners  would  be  carried  to  the  destination 
of  the  car  and  there  liberated,  thus  producing  a  new 
center  of  what  we  are  now  inclined  to  call  infestation. 
By  such  means  the  English  sparrow  has  spread  over 
much  the  larger  portion  of  the  American  continent. 
Few  birds  are  bold  enough  to  visit  a  railroad  car. 
Of  the  few  who  might  be  tempted,  most  are  timid 
enough  to  fly  on  the  first  approach  of  man.  Hence 
they  fail  to  gain  this  chance  of  spreading.  They  must 
remain  in  the  old  crowded  home.  Meanwhile  the 
sparrow,  thus  transported,  finds  a  new  home  with 
fewer  or  no  sparrows.  The  struggle  is  less 
keen.      More    of    his   kind    can   live.      His    boldness 


68  THE    MEANING    OF    EVOLUTION 

has  been  here  a  fit  quaHty  and  has  helped  him  in 
the  race. 

Man  is  only  slowly  coming-  to  be  a  city-dwelling 
animal.  Although  it  is  a  voluntary  process  with  him, 
he  still  usually  visits  the  country  with  much  enjoy- 
ment. He  has  not  as  yet  learned  to  adapt  himself 
thoroughly  to  the  city,  for  somehow  city  life  kills 
him.  Families  that  move  into  the  city  gradually  have 
a  smaller  number  of  children  in  each  generation  until 
shortly  the  family  is  wiped  out.  The  population  of 
the  city  must  constantly  be  replenished  from  the  coun- 
try. But  the  English  sparrow  is  more  adaptable  than 
are  the  people.  He  has  made  himself  at  home  in  the 
heart  of  the  biggest  city.  The  Wall  Street  canyon  is 
not  deep  enough,  nor  contracted  enough,  nor  free 
enough  of  food  to  blot  out  the  life  of  the  English 
sparrow.  At  the  heart  of  the  deepest  gully  among 
the  skyscrapers  of  our  biggest  cities  we  find  this  little 
bird  hopping  between  the  horses'  feet,  darting  out 
from  under  the  wheel  of  the  push-cart,  fluttering  only 
a  few  yards  to  a  place  of  safety,  to  return  at  once  to 
his  scanty  meal  upon  the  pavement  as  soon  as  oppor- 
tunity offers.  He  is  a  typical  city  dweller  and  has 
learned  to  thrive  there.  Again  in  this  matter  he  has 
distanced  other  birds  to  whom  the  city  is  more  deadly 
than  it  is  to  people. 

Another  very  important  element  in  his  fitness  for 


THE   UNDERLYING   IDEA 


69 


the  struggle  of  life  lies  in  the  fact  that  he  is  unafraid 
of  man.  He  is  wary  of  man;  by  which  I  mean  he  will 
quickly  fly  up  from  in  front  of  man's  feet.  It  is  ex- 
ceedingly difficult  to  catch  a  sparrow  in  one's  hand. 
It  is  far  easier  to  lure  a  pigeon  within  reach.  But 
the  sparrow,  when  escaping  your  hands,  comes  to  rest 
but  a  slight  distance  away,  only  to  elude  you  quite  as 
successfully  if  you  try  again.  If  the  sparrow  is  let 
severely  alone  he  becomes  more  and  more  familiar 
with  men,  flies  less  promptly,  and  goes  a  shorter  dis- 
tance, but  any  attempt  to  trap  him  renders  him  shy 
more  quickly  than  almost  any  other  bird  we  have. 
He  soon  learns  to  avoid  a  trap  in  which  his  compan- 
ions have  come  to  grief.  Those  who  would  poison 
or  trap  sparrows  must  change  constantly  the  base  of 
their  operations.  This  fearlessness  of  man  is  a  valu- 
able asset  to  the  bird,  for  it  is  an  important  defense 
against  other  foes. 

The  most  serious  enemy  the  birds  at  large  have, 
after  man  himself,  is  the  bird  of  prey.  Hawks  and 
owls  capture  a  large  quantity  of  our  smaller  birds. 
Now  the  hawks  and  owls  are  for  the  most  part  shy 
of  man.  They  have  gotten  a  bad  reputation,  espe- 
cially if  they  are  of  any  size,  because  of  their  more 
or  less  pronounced  proclivities  for  seizing  our  domes- 
tic poultry,  and  consequently  many  people  will  fire 
upon  a  hawk  or  an  owl  who  would  probably  fire  upon 


yO  THE    MEANING    OF    EVOLUTION 

no  otlicr  bird.  By  living  close  to  man  the  sparrow 
is  largely  saved  from  the  danger  of  capture  by  these 
carnivorous  creatures,  and  this  is  tiie  first  and  a  very 
important  element  of  the  advantage  to  the  sparrow  of 
living  near  man.  But  there  is  the  additional  advan- 
tage that  man  scatters  about  him,  in  one  way  or  an- 
other, a  very  considerable  amount  of  waste  food.  I 
have  suggested  that  the  seeds  in  the  droppings  of  the 
horse  form  a  large  proportion  of  the  sparrow's  food, 
and  horses  are  to  be  found  only  with  men.  In  the 
neighborhood  of  man's  home,  unless  he  has  become 
sanitary  to  a  degree  which  has  only  been  attained  in 
recent  years,  there  is  usually  more  or  less  garbage, 
kitchen  offal  of  one  sort  or  another.  To  this  the 
sparrow  has  easy  access  and  from  it  he  makes  many 
a  meal.  But  this  fearlessness  of  man  gives  him  still 
another  advantage  which  his  competitors  fear  to  use, 
it  provides  him  with  nesting  sites. 

Man  has  the  faculty  of  putting  up  ornamental  trim- 
mings on  his  house,  and  there  is  no  spot  the  sparrow 
chooses  more  willingly  in  which  to  build  his  nest  than 
the  ornamental  quirks  and  cornices  of  man's  archi- 
tecture. A  Corinthian  column  with  comely  leaves  in 
its  capital  seems  especially  designed  for  the  comfort 
of  the  sparrow,  and  his  distinctly  untidy  nest  is  the 
familiar  disfigurement  of  almost  every  ornate  public 
building.     These  arc  the  advantages  which  come  to 


I  THE   UNDERLYING   IDEA  7 1 

the  Sparrow  from  his  willingness  to  associate  with 
man,  and  there  are  comparatively  few  birds  with 
whom  he  must  share  them.  Few  birds  select  the  im- 
mediate neighborhood  of  man's  home  for  their  nests. 
They  may  live  in  the  neighboring  trees,  they  may 
haunt  his  orchard,  but  his  house,  for  the  most  part, 
they  decline  to  frequent. 

Still  another  quality  which  makes  for  success  in 
this  buccaneer  is  the  willingness  with  which  he  will 
vary  his  food  as  occasion  requires.  It  is  a  not  infre- 
quent characteristic  of  the  bird  family  that  each  spe- 
cies should  have  its  own  rather  restricted  diet.  Birds 
are  quite  particular  eaters,  and  many  of  them  will 
come  well  nigh  to  starvation  before  they  will  use  un- 
accustomed food.  The  sparrow,  on  the  contrary,  like 
man,  eats  almost  anything  he  comes  across  that  could 
reasonably  be  considered  edible.  He  belongs  to  a 
group  of  birds  which  are  structurally  adapted  to  crack- 
ing the  hard  coats  of  seeds.  This  group  of  birds  known 
as  the  finches  is  provided  with  the  sort  of  bill  familiar 
in  the  ordinary  canary  bird.  It  is  short,  heavy  at  the 
base,  comes  quickly  to  a  point,  and  is  firm  and  strong. 
With  it  the  bird  readily  breaks  through  the  hard  outer 
coat  of  most  seeds  and  feeds  upon  the  rich  cotyledons 
that  are  enclosed  within.  Nowhere  in  its  entire  stmc- 
ture  does  the  plant  crowd  so  much  nourishment  in  so 
little  space  as  it  does  in  the  seeds.     It  is  not  by  chance 


72  THE    MEANING    OF    EVOLUTION 

that  the  great  human  food  is  grain.  The  sparrow 
belongs  to  the  one  bird  group  that  makes  a  specialty 
of  such  seeds. 

Most  of  the  English  sparrow's  cousins  in  this  finch 
group  confine  themselves  rather  rigidly  to  this  diet. 
Here  the  variability  of  the  sparrow  again  gives  him 
the  advantage.  He  may  have  the  family  fondness  for 
seeds,  but  in  their  absence  he  can  be  content  with 
almost  anything  edible.  In  the  early  springtime,  when 
the  seeds  of  last  year  are  gone  and  those  of  the  new 
year  have  not  yet  been  produced,  the  sparrow  is  not 
averse  to  eating  young  buds  from  the  trees.  At  this 
time  he  is  not  unlikely  to  eat  our  sprouting  lettuce  and 
peas.  It  is  easy  to  be  severe  on  him  in  this  matter; 
but  for  a  creature  like  man,  who  has  the  same  tastes, 
who  eats  the  enormous  buds  of  the  cabbage,  the  cauli- 
flower, and  the  brussels  sprouts,  or  the  more  tender 
buds  which  he  calls  heads  of  lettuce,  it  seems  par- 
ticularly inappropriate  that  he  should  throw  stones  at 
this  little  creature  whose  tastes  are  so  similar  to  his 
own. 

While  seeds  are  more  suitable  for  an  elder  bird  they 
are  altogether  too  indigestible  to  be  the  food  of 
nestlings.  So  when  the  sparrow  finds  its  nest  full 
we  know  he  must  sally  forth  in  search  of  nourishment 
more  simple  of  digestion.  Now  for  a  few  weeks  he 
searches  assiduously,  catching  insects  and  caterpillars 


THE   UNDERLYING   IDEA  73 

of  various  kinds,  and  feeds  them  to  his  young.  This 
taste  passes  as  his  children  grow  older,  especially  as 
shortly  the  seeds  begin  to  ripen.  Now  is  the  time 
for  the  sparrow  to  fatten.  Now  he  is  eating  the 
food  for  which  he  was  really  built.  By  the  time  the 
wheat  is  ripe  there  are  sparrows  enough  about  to  form 
cjuite  a  flock,  and  when  these  settle  down  in  a  wheat, 
rye,  or  oats  field  and  feed  upon  the  grain,  meanwhile 
shaking  out  upon  the  ground  perhaps  as  much  as  they 
eat,  the  farmer  begins  to  realize  that  the  sparrow  is 
not  his  friend. 

When  winter  comes  the  struggle  for  existence 
among  the  birds  is  intensified,  and  comparatively  few 
of  them  dare  face  it.  Most  of  our  birds  betake  them- 
selves to  less  rigorous  cjuarters,  leaving  to  the  spar- 
row a  comparatively  small  number  of  competitors  for 
the  diminished  supply  of  food.  As  long  as  the  snow 
is  off  the  ground  the  sparrows  can  find  sufficient  sus- 
tenance. They  gather  themselves  into  groups  and  sally 
out  from  the  city  into  the  open  country.  The  imme- 
diate result  is  that  great  quantities  of  weed  seeds  are 
seized  upon  by  the  English  sparrow,  as,  indeed,  by 
every  other  finch  which  is  with  us  in  winter.  Per- 
haps we  have  not  given  the  little  fellow  credit  for 
the  good  he  does  at  this  particular  time,  for  the  rest 
of  the  account  truly  does  not  help  him  in  our  esteem. 

There  is  a  further  direct  advantage  in  the  sparrow's 


74  THE    MEANING    OF    EVOLUTION 

sociability.     One  robin  may  nest  in  the  vines  about 
your  purcli.     If  there  were  room  for  a  dozen,  scarcely 
more  than  one  would  be  likely  to  use  it.  because  he 
would  drive  away  any  other  robin  who  attempted  to 
siiare  the  neighborhood  with  him.     To  the  sparrow 
company-  is  always  in  order.     While  he  may  quarrel 
from  morning  until  night  with  his  fellow,  it  is  a  so- 
ciable quarrel  and  neither  would  willingly  forego  it. 
This   union   is  strength  among  birds,  as   with  man. 
Every  animal  is  safer  from  his  enemies  when  he  can 
have  the  constant  presence  of  others  of  his  own  kind. 
The  deer  that  stavs   in  the  herd  is  safer   from  the 
wolves.     It  is  only  when  the  latter  succeed  in  cutting 
out  some  weaker  or  less  sagacious  animal  that  these 
carnivorous  creatures  succeed  in  tearing  down  their 
prey.     I  think   the  superiority   of  the   sparrow  over 
most  of  our  common  birds,  when  considered  as  a  city 
dweller,  is  scarcely  understood.     Because  he  had  won 
in  the  race  with  other  birds  is  no  necessary  indication 
that  he  warred  directly  against  them.     Birdmen  often 
attribute  to  him  a  quarrelsome  disposition,  as  if  he 
actually  drove   other   birds   away.     It  almost   seems 
like  animosity  against  the  sparrow  to  speak  of  him  as 
attacking  blackbirds  and  crows.    It  is  a  cowardly  crow 
who  can  be  driven  away  by  a  sparrow,  and  if  the  two 
cannot  live  together  it  seems  to  me  certainly  to  the 
discredit  of  the  crow  and  not  of  the  sparrow.     I  be- 


THE    UNDERLYING    IDEA 


75 


lieve  the  truth  to  be  that,  while  the  sparrow  is  un- 
doubtedly a  quarrelsome  fellow,  his  bickerings  are  his 
form  of  social  converse  with  those  of  his  own  kind. 
A  quarrel  among  themselves  seems  not  to  indicate  ani- 
mosity, but  would  appear  to  be  the  sparrow's  idea  of 
conviviality.  It  rarely  leads  to  serious  results.  I  have 
never  seen  a  male  sparrow  trounce  any  other  bird  with 
half  the  vigor  that  I  have  occasionally  seen  the  mother 
sparrow  evince  when  she  caught  her  male  companion 
by  the  feathers  of  his  head,  hung  him  over  the  side 
of  the  limb,  and  vigorously  and  thoroughly  shook  him 
until  he  desisted  from  his  annoying  and  possibly  in- 
sulting attentions.  The  truth  of  the  matter  is  that  a 
colony  of  these  little  birds,  with  their  continual  social 
chatter,  including  their  quarrels,  makes  such  a  con- 
tinuous noise  that  the  ordinary  bird,  which  is  gen- 
erally of  rather  quiet  disposition,  is  too  much  annoyed 
by  the  unending  nuisance  to  find  the  neighborhood  at 
all  to  his  taste.  Where  a  large  number  of  sparrows 
have  gathered  together  the  conditions  are  such  as 
would  give  a  robin  or  a  bluebird  nervous  prostration, 
and  his  only  recourse  is  to  depart  to  a  neighborhood 
where  there  is  more  peace  and  quiet.  But  our  Eng- 
lish sparrow  is  not  only  better  fitted  for  the  struggle 
than  the  robins  and  bluebirds,  the  orioles  and  the 
wrens.  He  has  one  important  advantage  over  even 
his  own  sparrow  cousins.     The  males  are  handsome — 


76  THE    MEANING    OF    EVOLUTION 

much  more  so  than  the  females  or  than  their  sparrow 
cousins  in  general. 

In  the  song  sparrow,  field  sparrow,  chipping  spar- 
row, and  the  fox  sparrow  the  male  and  female  are 
very  nearly  alike  in  color.  It  often  becomes  neces- 
sary for  the  bird-man  to  examine  the  internal  organs 
of  the  bird  he  is  stuffing  before  he  can  certainly  de- 
cide its  sex.  But  there  is  no  difficulty  whatever  in 
telling  the  male  from  the  female  of  the  English  spar- 
row. The  male  is  far  the  more  ornate  bird.  His 
back  is  striped  with  a  richer  brown ;  his  head  has  two 
splendid  dashes  of  chestnut  over  the  eyes;  his  throat 
and  breast  are  splashed  with  red  and  lustrous  black; 
his  bill  is  a  clear  fine  black.  Altogether  the  bird  is 
strikingly  colored  for  a  sparrow,  and  this  characteris- 
tic is  the  more  remarkable  when  we  see  how  quiet  and 
somber  is  his  more  modest  mate.  This  brilliancy  of 
male  plumage  in  the  presence  of  the  somber  color  of 
his  mate  would  seem  to  indicate  that  the  English  spar- 
row is  eye-minded  rather  than  ear-minded.  It  is  true 
among  human  beings  that  most  of  them  are  eye- 
minded.  That  is  to  say,  they  notice  things  with  their 
eyes  chiefly.  Memories  they  have  are  memories  of 
things  seen;  recollections  of  their  friends  bring  up 
the  appearance  of  their  friends.  Their  language  is 
full  of  metaphors  which  imply  form  and  shape.  But 
occasionally  we  come  across  an  ear-minded  person. 


THE    UNDERLYING   IDEA 


77 


He  remembers  voices  quite  as  well  as  he  remembers 
faces.  To  him  music  is  an  unending  delight,  and 
painting  and  sculpture  fall  into  a  distinctly  secondary 
place.  This  is  ear-mindedness.  Now,  most  of  the 
sparrows  seem  to  be  ear-minded,  at  least  as  far  as 
their  recognition  of  their  mates  are  concerned.  In 
this  group  beauty  of  song  is  developed  many  times 
oftener  than  is  especial  ornateness  of  plumage.  The 
bird-lover  who  is  himself  keen  of  ear  is  never  tired  of 
listening,  when  in  the  field,  for  the  two  low  notes  with 
which  the  vesper  sparrow  introduces  a  song,  the  rest 
of  which  is  not  at  all  unlike  the  one  of  his  song-spar- 
row cousin.  The  field  sparrow  begins  more  like  the 
song  sparrow,  but  ends  with  an  often  repeated  note, 
which  not  a  little  resembles  in  general  character  the 
somewhat  more  monotonous  song  of  the  grasshopper 
sparrow  or  of  the  chippy.  In  comparison  with  these 
melodious  birds  the  English  sparrow  makes  no  show- 
ing whatever.  His  voice  is  harsh  and  querulous,  al- 
though very  occasionally  it  is  possible  for  the  bird- 
lover  to  detect  a  note  or  two  which  would  indicate 
that,  if  he  were  properly  educated,  his  voice  might 
amount  to  something.  He  wins  his  wife  not  by  his 
pleasant  voice,  but  by  his  attractive  appearance  and 
his  winning  ways.  We  have  every  right  to  infer 
from  the  character  of  its  fellow  birds  of  the  sparrow 
family  that  once  the  female  and  male  sparrow  were 


7^  THE    MEANING    OF    EVOLUTION 

colored  al)oiit  alike.      But   Madam   English   Sparrow 
was  apparently   eye-niindcd   rather  than   ear-minded. 
AMiatever  pleasant  voice  a  suitor  might  have  seems 
to  have  been  to  her  without  attraction,  and  there  was 
nothing  to  encourage  him  in  developing  it,  nor  was 
she  likely  to  mate  with  him  for  it  and  transmit  it  to 
her  male  children.     On  the  other  hand,  let  a  suitor 
appear  in  whom  a  more  brilliant  coloring  proclaimed 
his  superior  vigor,  and  this  seems  to  catch  her  eye  at 
once.     The  less  accomplished  rival  in  the  tournament 
of  love  seems  to  have  been  already   forgotten.      To 
their    children    these    successful    characteristics    w^ere 
naturally  handed  on  and  led  to  equal  success  on  their 
part.     If  any  of  these  children  possessed  this  badge 
of  honor  in  a  more  than  ordinary  degree,  he  was  the 
more  likely  to  win  a  mate  and  thus  again  the  oppor- 
tunity of  passing  on  to  his  offspring  his  own  distinct 
advantage.     Generation  by  generation  the  males  have 
l)ecome  more  beautiful  and  the  females  more  discrimi- 
nating.    That  the  bird  is  either  instinctively  or  actu- 
ally conscious  of  this  advantage  would  appear  from 
the  constant  Huffing  of  his  feathers  and  spreading  of 
his  highly  colored   wings  with  which  he  evinces  his 
admiration  for  his  ladylove.     Even  the  most  hardened 
dweller  in  the  city  can  scarcely  have  failed  to  see  the 
sparrow  spread  his  wings,  fluff  his  feathers,  and  sink 
close  to  the  ground,  twirling  and  gyrating  about  the 


THE    UNDERLYING    IDEA 


79 


object  of  his  affection.  It  must  give  him  a  shock  to 
see  how  often  she  proves  temporarily  or  hypocriti- 
cally indifferent  to  the  demonstrative  proceedings.  In- 
deed they  may  terminate  in  a  thorough  trouncing  of 
the  male  on  the  part  of  the  lady  of  his  affections. 
Now  this  preference  for  color  over  song  must  have 
evidently  evolved  in  connection  with  the  development 
of  social  habits  in  the  English  sparrows.  His  cousins 
of  the  fields,  our  native  sparrows,  are  much  less  social, 
much  less  likely  to  be  met  with  in  flocks.  To  birds 
who  scatter  more,  beautiful  song  is  a  great  advantage. 
It  can  be  heard  at  a  long  distance.  But  when  birds 
flock  together  a  much  better  advantage  is  that  of  beau- 
tiful clothing,  added  to  alluring  ways. 

But  we  have  not  nearly  exhausted  the  catalogue  of 
the  traits  belonging  to  our  little  friend  which  give 
him  the  advantage  over  other  birds  in  the  struggle 
for  life.  His  ability  to  remain  with  us  in  winter  when 
most  birds  are  gone  stands  him  in  good  stead. 

It  is  readily  observed  by  one  who  pays  the  least  at- 
tention to  outdoor  life  that  winter  finds  us  with  com- 
paratively few  birds.  North  of  Maryland  and  the 
Ohio  River  the  robin  is  practically  absent  in  the  win- 
ter, except  in  much  diminished  numbers  close  to  the 
border.  The  bluebird  is  similarly  absent;  the  great 
flocks  of  blackbirds  are  gone ;  the  bobolink  is  missing 
entirely;  the  thrush  and  the  catbird  have  all  left;  the 


80  THE    MEANING    OF    EVOLUTION 

flicker  and  rcd-hcadcd  woodpecker  are  also  spending 
their  winter  in  the  South.  The  great  mass  of  our 
bird  population  has  left  us  until  warmer  weather  shall 
bring  back  to  us  once  more  our  feathered  friends.  It 
is  true  that  we  are  south  to  the  snowbirds  or  j uncos, 
and  their  little  slate-colored  bodies,  with  their  light 
breasts  and  their  white  on  each  side  of  the  tail,  make 
our  bare  hedge  rows  brighter  by  their  presence.  A 
few  of  our  birds  like  the  song  sparrow  and  the  car- 
dinal are  hidden  away  in  the  thicket,  and  have  not 
all  joined  their  comrades  in  the  south. 

The  English  sparrow  was  once  probably  cjuite  as 
migratory  as  any  of  the  rest  of  these,  but  a  great 
change  has  come  over  his  habits.  With  his  newly 
acquired  fondness  for  the  haunts  of  men  he  has  suf- 
fered a  change  in  this  respect  also.  Whatever  may 
have  been  his  reason  for  migrating,  it  no  longer  holds. 
He  now  finds  himself  quite  able  to  stand  the  cold  of 
winter.  Accordingly  he  never  leaves  us,  except  very 
temporarily.  When  the  migrating  season  comes  the 
sparrows  of  the  neighborhod  are  very  likely  to  gather 
themselves  together  in  a  single  group  and  take  to  the 
neighboring  country.  I  believe  this  flocking  on  their 
part  at  this  time  of  the  year  is  a  remnant  of  the  old 
migratory  habit.  Until  snow  covers  the  ground  the 
sparrow  is  not  likely  to  be  seen  again  in  such  num- 
bers in  the  city.     The  advantage  the  sparrow  gains 


( 


* 


THE   UNDERLYING   IDEA  8l 

over  his  competitors  by  not  going  south  does  not  ap- 
pear during  winter.  When  spring  comes,  however,  his 
gain  is  evident.  He  has  his  choice  of  all  the  nesting 
sites  in  the  region.  .When  the  migratory  birds  re- 
turn every  first-class  place  is  filled  by  a  sparrow's  nest. 
Nothing  but  second  choice  situations  remain,  and  with 
these  the  late  comers  must  be  content.  W^hen  we  con- 
sider how  much  the  safety  of  the  next  generation  de- 
pends upon  the  security  of  the  young  while  helpless  in 
the  nest,  we  appreciate  what  the  English  sparrow  has 
gained  by  staying  throughout  the  year.  Often  while 
the  season  is  so  inclement  that  it  would  seem  there  is 
still  danger  of  frost,  the  sparrow  builds  her  nest.  All 
sorts  of  places  are  open  to  her  choice.  She  will  find 
a  protected  corner  under  a  roof,  above  a  spout,  in  the 
corner  of  the  porch,  behind  an  open  shutter,  in  the 
vines  against  the  side  of  the  house,  on  top  of  an  old 
robin's  nest  in  the  tree,  in  the  bird  boxes  which  have 
been  put  up  for  more  desirable  creatures;  anywhere 
and  everywhere  this  industrious  little  mother  is  liable 
to  build  her  nest.  Her  husband  will  help  her  more  or 
less  in  the  task,  often  bringing  material  and  helping 
to  place  it  in  the  negligent  pile  of  which  their  nest  is 
composed.  But  he  does  a  good  deal  more  fussing  and 
cheering  up  than  he  does  actual  work,  and  she  seems 
to  depend  much  upon  his  cheerful  presence  for  her 
happiness.     It  is  hard  to  discourage  Madam  Sparrow 


82  THE    MEANING    OF    EVOLUTION 

when  once  she  has  set  her  mind  on  home-making.  A 
bird-lover,  some  time  since,  reported  how  a  pair  of 
sparrows  had  started  to  build  a  nest  upon  his  lawn. 
He,  wishing  to  interfere  with  the  process,  took  a  small 
rifle  and  shot  the  male  bird.  \\'ithin  twenty  minutes 
the  female,  who  had  scouted  round  the  neighborhood, 
returned  with  another  mate  and  resumed  her  nest- 
building  process.  Again  he  interjected  the  tragic  note 
into  her  life  by  shooting  her  second  husband,  only  to 
find  her  start  out  in  pursuit  of  a  third,  with  whom  she 
returned  in  the  course  of  an  hour.  He  felt  that  by 
this  time  he  had  interfered  with  her  domestic  happi- 
ness as  much  as  he  had  any  right  to  do,  and  suffered 
her  to  continue  her  housekeeping  with  her  third  hus- 
band without  further  molestation.  I  imagine  it  would 
have  puzzled  both  birds  to  tell  who  was  the  father  of 
the  nestlings  who  appeared  two  weeks  later. 

Not  only  do  sparrows  nest  early,  they  nest  often. 
I  suggested  to  one  of  my  students  that  she  locate  as 
early  in  the  season  as  she  could  the  nest  of  a  pair  of 
English  sparrows,  which  was  sufficiently  accessible, 
and  that  she  keep  it  under  observation  at  intervals  of  a 
few  days  throughout  the  summer.  In  the  fall  she 
came  to  me  with  glowing  eyes  and  gave  me  her  re- 
port. "It  is  simply  great,"  she  said.  "I  never  went 
to  that  nest  a  single  time  this  summer  to  find  it  empty. 
When  I  first  got  there  I  found  four  eggs;  after  a 


THE    UNDERLYING   IDEA  83 

while  these  hatched  out,  and  the  young  were  on  the 
nest  until  they  were  old  enough  to  fly;  but  before  they 
had  left  she  had  slipped  a  fresh  egg  among  them, 
ready  to  start  a  new  batch.  Whenever  I  saw  the  nest 
throughout  the  entire  summer,  I  found  in  it  either 
eggs,  or  young,  or  both."  Such  reproductive  energy 
as  this  is  hard  to  beat;  compared  with  this  rate  of  in- 
crease, the  ordinary  bird  is  the  exponent  of  race  sui- 
cide. How  can  a  robin  hope  to  compete  with  this 
family  industry?  What  can  a  bluebird  offer  that  will 
approach  such  chances  of  a  worthy  successor  when  his 
work  shall  be  finished  ? 

These,  then,  are  the  most  important  points  in  which 
the  English  sparrow  has  varied  from  his  sparrow 
cousins  and  made  of  himself  the  most  successful  town 
dweller  in  the  bird  world.  He  has  become  clannish 
and  gained  the  advantages  of  cooperation.  He  has 
used  man's  highways  and  cars  by  means  of  which  to 
expand  his  area.  He  has  cultivated  the  presence  of 
man  and  thus  gained  protection  from  his  enemies, 
food  from  man's  waste,  and  nesting  sites  on  man's 
house.  He  has  assumed  a  varied  diet.  The  male  has 
become  handsome.  He  has  given  up  migrating,  and 
thus  secured  the  best  nesting  sites.  He  has  learned 
to  produce  many  offspring.  With  all  his  versatility, 
why  should  he  not  succeed? 

Thrown  into  competition  with  our  native  birds,  he 


84  THE    MEANING    OF    EVOLUTION 

easily  beats  them  on  their  own  ground.  He  survives 
against  the  competition  of  birds  which  seem  to  us 
more  estimable  in  every  way.  The  very  fact  that  he 
survives  proclaims  his  superiority  over  them,  and 
shows  that  our  criterion  is  not  the  one  by  which  na- 
ture judges.  We  like  the  birds  which  serve  our  pur- 
pose. We  admire  the  brilliant  plumage  of  the  jay, 
cardinal  and  goldfinch.  We  love  the  mellow  notes  of 
the  woodthrush,  and  of  the  veery,  the  clear,  rollicking 
outpourings  of  the  bobolink,  the  musical  love  song 
of  the  brown  thrasher,  the  cheerful  scolding  of  the 
wren.  We  are  fond  of  the  birds  who  busy  them- 
selves taking  the  insects  out  from  among  our  grain 
and  from  off  our  fruit  trees.  We  can  only  understand 
the  value  of  the  bird  to  nature  when  he  is  valuable  to 
us.  So,  because  the  English  sparrow  does  little  that 
is  to  our  advantage  and  much  that  is  to  our  annoy- 
ance, he  is  in  our  estimation  a  reprobate  and  an  un- 
ending nuisance. 

All  sensible  bird-men  must  clearly  acknowledge  that 
he  is  a  very  undesirable  citizen.  I  write  the  above 
ncntence  to  show  that  I  realize  the  whole  duty  of  the 
bird-lover  in  the  matter  of  the  sparrow.  This  pestifer- 
ous creature  should  be  exterminated  by  traps,  by  grain 
soaked  in  alcohol,  or  strychnia,  by  fair  means  or  foul. 
But  personally,  I  am  taking  no  share  in  his  destruc- 
tion.   Any  bird-lover,  after  reading  the  foregoing  ac- 


THE    UNDERLYING   IDEA  85 

count,  can  scarcely  have  missed  the  undercurrent  of 
my  affection  for  the  little  rascal.  He  is  a  thorough 
optimist;  he  is  absolutely  persistent;  no  hardship 
seems  to  dampen  his  ardor.  His  heart  is  valiant 
above  that  of  most  birds  so  that  he  has  dared  to  make 
of  man  his  near  neighbor  when  other  birds  consider 
him  their  worst  enemy.  I  love  him  for  it.  When  I 
am  in  the  midst  of  a  big  city  with  its  cliffs  of  offices 
and  its  gorges  of  paved  streets,  it  is  to  me  a  cheer 
and  a  delight  to  see  this  happy  little  fellow  who  has 
adapted  himself  to  circumstances  against  which  no 
other  bird,  excepting  the  pigeon,  can  cope.  I  confess 
that  it  would  be  with  regret  that  I  should  see  him  dis- 
appear from  the  landscape.  I  have  missed  a  long  line 
of  spring  peas  through  his  ravages,  and  he  has  objec- 
tionably decorated  many  places  about  my  own  home. 
But  I  have  yet  the  first  violent  hand  to  lay  upon  the 
sparrow,  and  I  doubt  whether  my  hand  is  ever  to  be 
reddened  with  his  blood. 

I  am  going  to  ask  bird-men  to  forgive  me  if  I  say 
that  I  believe,  although  I  speak  only  from  general 
impression,  and  not  from  careful  research,  that  the 
sparrow  within  the  past  eight  years  has  reached  his 
equilibrium  in  the  neighborhood  of  Philadelphia  and 
is  growing  no  more  abundant.  Meanwhile  another 
and  very  desirable  state  of  affairs  is  arising.  Bird 
love  and  bird  protection  are  so  active  in  this  neigh- 


86 


THE    MEANING    Oi"    EVOLUTION 


borhood  that  there  is  growing  to  be  a  new  race  of 
birds  Avho  lack  the  fear  of  man  their  ancestors  justly- 
had.  Under  these  conditions  the  wild  birds,  which 
for  a  while  we  believed  to  have  been  completely  driven 
out  by  the  sparrow,  are  rapidly  returning  to  our  vil- 
lages and  towns,  and  we  have  many  more  robins  and 
catbirds,  wrens  and  flickers  than  we  had  ten  years  ago. 
We  have  seen  the  w^orst  of  the  English  sparrow;  he 
has  now  found  his  equilibrium. 


i 


CHAPTER  IV 

Adaptation  for  the  Individual 

Among  the  standard  books  of  the  classical  curricu- 
lum in  the  denominational  college  of  thirty  years  ago 
was  a  volume  which  I  suppose  has  practically  disap- 
peared from  such  courses.  It  delighted  many  of  its 
students  for  a  reason  entirely  different  from  that 
which  the  author  meant  should  be  its  taking  feature. 
It  was  Paley's  "Natural  Theology."  The  author 
started  with  a  story  of  a  watch  found  by  a  savage. 
This  child  of  nature  was  supposed  to  examine  its 
mechanism  and  to  infer  that  the  watch  was  made  for 
a  definite  purpose.  As  I  remember,  he  was  even  sup- 
posed to  discover  that  its  purpose  was  to  mark  time. 
It  was  at  least  to  become  clear  to  his  savage  mind  that 
this  was  no  chance  object,  but  was  the  definite  product 
of  a  designing  mind.  Having  brought  this  hypotheti- 
cal savage  to  these  conclusions,  the  author  turned  him- 
self to  savages  nearer  home  who  fail  to  see  design  in 
nature.  The  book  takes  up  a  great  many  cases  of  in- 
teresting facts  in  animals  and  plants  as  clearly  show- 
ing evidences  of  design  as  did  the  watch  our  savage 
picked  up.     But  the   inference  we  were  expected  to 

87 


88  THE    MEANING    OF    EVOLUTION 

draw  was  that  the  design  shown  in  nature  argued 
clearly  for  a  Designer  above  nature;  in  other  words, 
that  nature  was  unintelligible  without  God.  Every- 
one in  the  class  believed  in  God  without  this  prelim- 
inary, and  consequently  the  book  was  unnecessary,  so 
far  as  we  were  concerned.  We  started  with  the  con- 
dition of  mind  which  the  author  hoped  to  produce. 
One  effect  the  book  did  have;  in  the  absence  of  any 
other  reputable  course  in  zoology,  it  gave  us  an  as- 
tonishing collection  of  interesting  facts  about  animals. 

Some  of  Paley's  statements  were  certainly  peculiar. 
His  Malay  pig  with  its  upper  teeth  wonderfully 
curved  was  said  to  be  in  the  habit  of  hanging  its  head 
upon  a  bush  while  it  slept,  in  order  to  save  the  strain 
upon  its  porcine  neck.  This  was  too  much  even  for 
our  credulity.  None  the  less  the  impression  made 
upon  some  of  us  by  the  evidence  for  design  in  nature 
has  never  left  us. 

Among  many  scientists  to-day  it  is  supposed  to  be 
crude  to  speak  of  purpose  in  nature,  and  there  is  rea- 
son for  their  attitude.  But  the  statement  that  there  is 
no  such  plan  conveys  to  the  ordinary  thinker  a  mean- 
ing that  is  far  more  erroneous  than  could  possibly  ex- 
ist in  his  mind  should  he  believe  implicitly  in  design 
and  purpose.  As  between  design  in  the  universe  in 
the  usual  sense  of  the  word,  and  a  purely  accidental 
connection  of  events  in  the  universe,  there  can  be  no 


ADAPTATION    FOR   THE   INDIVIDUAL  89 

doubt  as  to  the  choice.  The  truth  is  far  better  ex- 
pressed by  the  word  design  than  by  the  chaos  which 
is  the  alternative  idea  in  the  average  mind.  In  these 
later  years  we  have  come  to  use  a  different  word.  We 
now  conjure  in  such  connection  with  the  word  adapta- 
tion. In  every  animal  and  every  plant  the  trained 
eye  sees  unending  examples  of  adaptation;  that  is, 
of  a  fittedness  to  the  work  it  has  to  do.  The  modern 
scientist  feels  sure  not  only  that  the  animal  is  fitted  to 
his  work,  but  that  he  has  been  so  fitted  by  the  work; 
that  the  very  use  he  makes  of  his  organs  has  deter- 
mined their  structure.  This  work  has  decided  that 
the  structure  which  he  has  is  the  structure  that  shall 
survive  and  shall  produce  other  structures  like  itself. 
Adaptation  therefore  does  not  simply  express  the  idea 
that  the  animal  is  adjusted  to  its  surroundings,  but 
it  further  suggests  that  the  animal  by  gradual  process 
has  become  thus  adjusted.  The  word  adaptation  ap- 
plies not  simply  to  the  result,  but  also  to  the  process. 
The  scientist  does  not  consider  the  animal  a  final  and 
complete  result.  He  thinks  it  still  in  a  state  of  flux, 
and  so  long  as  its  line  lasts  it  will  be  in  a  state  of  flux. 
Change  is  about  it  on  every  side,  and  it  must  adapt 
itself  to  this  change  or  it  will  pass  away.  It  may  ad- 
just itself,  as  has  been  previously  stated,  by  moving  to 
another  environment  in  which  it  feels  more  at  home, 
but  unless  it  does  this,  if  there  come  much  change  in 


90  THE    MEANING    OF    EVOLUTION 

its  present  surroundings,  it  must  either  meet  the  diffi- 
culty by  altering  itself,  or  it  must  give  up  the  strug- 
gle. The  alteration  is  unconscious  so  far  as  the  ani- 
mal is  concerned.  It  is  seriously  to  be  doubted 
whether  there  is  any  recognition  of  the  process  on  the 
part  of  any  animal  excepting  man.  But  though  the 
process  be  unconscious,  it  is  none  the  less  there. 
Slowly  and  gradually  the  animal  and  the  environment 
are  becoming  adjusted  to  each  other. 

While  it  is  exceedingly  difficult  to  lay  our  hands  on 
any  animal  which  is  at  present  visibly  changing  its 
structure,  it  is  not  hard  to  find  closely  related  animals. 
These  are  nearly  alike  in  structure  in  most  respects. 
In  a  few  points,  however,  they  may  differ  materially, 
and  these  points  are  often  directly  concerned  with  dif- 
ferent habits  of  life.  Considered  in  this  aspect,  these 
adaptations  of  a  single  organ  separately  examined 
form  an  excellent  argument  in  favor  of  that  gradual 
alteration  of  the  entire  organism  which  evolution  sug- 
gests. 

The  most  primitive  struggle  in  which  an  animal  can 
possibly  engage  is  the  effort  to  maintain  its  own  life 
and  vigor.  This  struggle  will  result  in  certain  adapta- 
tions for  the  individual,  adjustments  which  make  for 
the  safety  of  the  animal  himself.  These  form  the  sub- 
ject matter  of  the  present  chapter. 

The  farther  up  the  animal  kingdom  we  pass  in  the 


ADAPTATION    FOR   THE   INDIVIDUAL  9 1 

study  of  adaptation,  the  more  likely  we  are  to  find 
changes  which  have  but  little  bearing  on  the  safety  of 
the  individual.  They  work  for  the  good  of  the  entire 
species,  sometimes  to  the  distinct  disadvantage  of  the 
individual.  The  King  Salmon  may  make  its  long  run 
to  the  headwaters  of  our  western  rivers,  deposit  its 
eggs,  have  them  fertilized,  and  then  float  down  to 
death.  But  it  does  not  die  before  abundant  prepara- 
tion has  been  made  for  the  continuance  of  the  race. 
Such  adaptation  for  the  good  of  the  species  will  be 
considered  in  the  next  chapter. 

The  first  and  most  important  struggle  any  animal 
has  to  enter  is  the  never-ending  battle  for  its  food. 
Occasionally  there  is  a  similar  straining  after  the  air 
it  breathes.  But  ordinarily  air  is  sufficiently  abundant, 
except  to  animals  living  in  the  water,  where  the  sup- 
ply is  always  more  or  less  restricted  and  easily  be- 
comes exhausted.  But  food  is  the  constant  need  of 
every  organism,  and  most  creatures  die  for  lack  of  it. 
In  this  struggle  the  animal  is  pitted  against  those  of 
his  own  kind,  rather  than  against  those  of  other  spe- 
cies. Even  his  brother  is  his  enemy,  for  he  desires 
the  same  food.  In  many  a  nest  of  birdlings  one  of 
them  fails  to  reach  its  development  simply  because  the 
parent  either  is  unable  to  find  or  it  cannot  carry 
enough  food  to  satisfy  all  the  hungry  mouths  in  the 
same  nest.     Before  the  nestlings  are  ready  to  take 


y 


92  THE    MEANING    OF    EVOLUTION 

their  place  in  the  struggle  for  life  outside  and  hunt 
their  own  living,  one  or  more  of  them  has  succumbed. 

After  the  battle  for  food  comes  the  struggle  for 
shelter.  For  most  animals  there  is  no  such  thing  as  ./ 
shelter.  They  are  exposed  to  the  inclemencies  of  the 
weather  and  to  the  depredations  of  their  enemies  with- 
out the  means  of  retiring  into  any  situation  which 
might  protect  them.  In  the  higher  animals,  especially 
when  they  are  warmer  blooded  and  their  bodies  must 
be  kept  at  a  higher  temperature,  some  form  of  cover- 
ing has  come  to  be  almost  universal. 

Though  comparatively  few  animals  are  prepared  to 
seek  shelter  from  the  cold,  all  of  them  have  enemies 
against  whom  they  must  battle.  These  foes  may  wish 
to  eat  them  or  may  simply  wish  to  get  them  out  of 
the  way.  In  either  event  this  struggle  is  so  persist- 
ent and  so  keen  that  after  starvation  it  is  probably  th^ 
source  of  the  largest  loss  to  the  animal  kingdom. 

Considering  first  the  feeding  habits  of  animals,  we 
find  they  are  exceedingly  varied.  Some  creatures  sim- 
ply engulf  other  and  more  minute  animals,  often  only 
microscopic  in  size,  in  such  quantities  as  to  satisfy 
their  hunger.  Others,  feeding  upon  larger  plants  or 
animals,  must  have  some  means  of  breaking  off  par- 
ticles of  this  food;  still  others  confine  themselves  en- 
tirely to  nutritious  fluids,  and  must  have  organs 
adapted  to  this  particular  type  of  food. 


ADAPTATION    FOR   THE   INDIVIDUAL  93 

Insects  are  so  common  that  anyone,  who  cares  to, 
may  easily  verify  what  is  here  described.  It  will  take 
nothing  but  a  clear  observant  eye  and  a  little  patience 
to  make  out  what  is  suggested.  Each  of  our  com- 
mon insects  has  one  of  two  clearly  defined  habits  in 
the  matter  of  food.  Either  it  eats  solid  food,  which 
must  be  made  fine  before  it  can  be  taken  into  the 
mouth,  or  it  feeds  upon  liquids.  These  liquids  may 
be  easily  accessible  like  the  nectar  of  flowers,  in  which 
case  one  sort  of  mouth  will  serve;  or  they  may  be  the 
juices  inside  the  tissues  of  animals  and  plants,  when 
an  entirely  different  type  of  mouth  must  be  employed 
in  their  acquisition.  Perhaps  the  most  easily  found 
representative  of  the  biting  type  of  mouth,  which 
breaks  up  solid  food,  will  be  seen  in  the  common 
grasshopper.  Doubtless  each  one  of  my  readers  has 
at  some  time  taken  a  grasshopper  into  his  hand,  and, 
holding  the  tip  of  his  finger  against  the  insect's 
mouth,  has  promised  the  creature  its  freedom  on  con- 
dition that  it  disclosed  its  reprehensible  habit  of  chew- 
ing tobacco.  The  grasshopper  surely  complied,  and  I 
trust  the  promiser  was  as  good  as  his  word.  The 
grasshopper's  head  is  so  placed  that,  while  it  is  at  the 
front  of  its  body,  the  mouth  is  directly  on  the  under 
side  of  its  head,  while  the  eyes  are  at  the  top  of  the 
front  of  its  face.  Under  these  circumstances  it  can- 
not see  what  is  going  into  its  mouth,  and  this  makes 


94  THE    MEANING    OF    EVOLUTION 

an  interesting  variation  of  conditions  to  which  it  must 
adapt  itself.    The  means  by  which  it  accomphshes  this 
will  be  clearer  if  the  mouth  of  the  grasshopper  be 
compared  with   our  own.     Our  lips   are   upper  and 
lower,  but  the  grasshopper  has  a  front  lip  and  a  hind 
one.     The  broad  front  lip  is  easily  seen  at  the  for- 
ward side  of  the  mouth.     Just  behind  it,  serving  the 
purpose  of  our  teeth,   is  a  pair  of  hard  jaws  with 
horny  tips  upon  them,   which  serve   to  break  small 
pieces  from  its  food.    While  our  jaws  and  those  of  all 
other  backboned  animals  work  up  and  down,  so  that 
we  may  be  said  to  have  an  upper  and  lower  jaw,  the 
grasshopper  and  all  of  his  insect,  crab,  or  spider  re- 
lations, which  have  jaws  at  all,  have  them  right  and 
left,  and  they  work  from  side  to  side.     Behind  these 
harder  mouth  parts  is  found  a  pair  of  softer  jaws, 
each   of  which  has  on   it  a  little   finger-like   feeler. 
With  this  pair  the  insect  holds  its  food  while  the  hard 
jaws  break  it  to  pieces.     The  hind  lip  follows,  and  is 
also  provided  with  short  finger-like  feelers.     The  feel- 
ers on  the  hind  lip  and  on  the  soft  jaw  are  necessary 
because  the  eyes  are  so  placed  as  not  to  be  able  to  see 
what  goes  into  the  mouth,  hence  the  insect  must  make 
up  for  the  loss  of  sight  by  the  addition  of  touch.    The 
same  type  of  mouth  as  the  grasshopper  has  will  be 
found  among  the  beetles.     Here  the  males  sometimes 
have  the  hard  jaws  so  enormously  enlarged  that  they 


ADAPTATION    FOR    THE   INDIVIDUAL  95 

are  known  as  pinchers  and  have  given  to  their  owners 
the  name  of  pinching  bugs.  All  insects  with  such 
jaws  as  these  use  them  for  breaking  up  solid  food. 

A  glimpse  at  the  mouth  of  the  butterfly  captured 
on  an  adjoining  flower  will  show  a  most  remarkable 
variation  from  that  seen  in  the  grasshopper.  Prac- 
tically all  of  the  mouth  parts  mentioned  are  present  in 
this  insect,  and  its  early  ancestors  had  their  organs 
practically  like  those  of  the  grasshopper.  Now  they 
are  so  modified  and  united  with  each  other  as  to  be 
almost  unrecognizable.  The  pair  of  soft  jaws  has 
become  very  much  elongated,  and  they  lock  together 
in  such  a  way  as  to  enclose  a  hollow  space  between 
them  through  which  the  creature  can  suck  its  fluid 
food.  Not  only  have  these  soft  jaws  joined  together, 
but,  because  they  have  become  so  much  elongated 
when  not  in  use,  they  must  be  coiled  up  like  a  watch 
spring  and  laid  between  two  hairy  lip-like  processes 
which  correspond  in  reality  to  the  two  finger-like  feel- 
ers of  the  grasshopper's  hind  lips. 

The  butterfly,  lighting  upon  the  corolla  of  the 
flower,  uncurls  this  long  "tongue,"  and  through  its 
hollow  center  pumps  up  into  its  crop  the  nectar  which 
the  flower  has  stored  in  its  base.  When  the  butterfly 
comes  to  get  the  nectar  from  the  flower,  it  rubs  upon 
its  own  hairy  body  pollen  from  the  stamens  of  the 
flower  and  carries  it  to  the  pistil  of  the  next  flower 


96  THE    MEANING    OF    EVOLUTION 

of  the  same  kind  which  it  visits.  Most  of  us  have  at 
some  time  sucked  the  nectar  from  the  back  of  a  torn 
honeysuckle  blossom  and  approved  the  taste  of  the  but- 
terfly in  this  matter.  If  the  airy  creature  be  watched 
as  it  lights  upon  a  flower,  it  will  not  l^e  difficult  to 
see  it  uncurl  this  long  tongue  and  probe  the  depths  of 
the  flower.  If  the  butterfly  be  taken  in  the  hand  and 
the  tip  of  a  pin  inserted  in  the  center  of  the  coiled 
tongue,  it  can  be  uncoiled  without  the  slightest  harm 
to  the  butterfly. 

Insects  which  wish  to  use  for  their  food  the  juices 
of  other  animals  or  of  plants  do  not  find  them  so  easy 
to  gather.  In  the  mosquito  most  of  the  mouth  parts 
are  developed  into  slender  pointed  bristles  wrapped  in 
a  hind  lip.  These  bristles  serve  to  puncture  the  skin 
of  the  creature  attacked,  while  the  curled  lip  serves  as 
a  tube  through  which  the  blood  may  be  extracted. 

If,  while  sitting  on  the  porch  on  a  warm  summer 
evening,  mosquitoes  begin  to  annoy,  let  one  of  them 
at  least  serve  to  show  his  method  of  procedure  before 
he  is  destroyed.  Allow  the  creature  to  alight  upon  the 
back  of  your  hand  and  slowly  raise  the  arm  until  the 
eye  looking  at  near  range  can  see  the  head  of  the 
mosquito,  which,  by  the  way,  is  sure  to  be  a  female. 
Males  in  this  species  are  entirely  harmless.  They 
never  eat  after  they  have  grown  up;  that  is,  after 
they  are  truly  mosquitoes.     But  the   female  is  very 


ADAPTATION    FOR   THE   INDIVIDUAL  97 

assiduous.  Alternately  raising  and  lowering-  her  lan- 
cets from  either  side,  she  pierces,  then  saws,  her  way 
down  through  the  flesh  until  she  has  buried  her  in- 
struments in  her  victim  and  her  head  rests  against 
her  prey.  Now  a  pumping  motion  of  the  abdomen 
will  be  apparent,  and  this  continues  its  accordion-like 
action  until  it  becomes  more  and  more  distended.  The 
insect  only  gives  up  its  task  when  the  entire  abdomen 
is  swollen  into  a  great  red  ball  of  blood.  The 
mosquito  will  now  slowly  withdraw  its  instruments 
and  retire  from  the  scene,  if  permitted  to  do  so.  If 
there  is  any  fear  of  annoyance  from  the  bite,  a  drop 
of  ammonia  immediately  applied  will  counteract  any 
irritation  which  would  have  been  produced  by  the 
saliva  of  the  mosquito.  The  insect  is  not  intentionally 
vicious  in  this  procedure.  It  is  simply  gathering  its 
own  natural  food,  though  this  does  not  make  it  less 
annoying  to  us  since  we  are  its  victims.  The  swell- 
ing produced  after  the  bite  is  the  result  of  the  action 
of  the  saliva  the  mosquito  injected  into  the  wound. 
The  opening  through  the  tongue  is  so  small  that  blood 
would  readily  clot  inside  the  tube  and  prevent  its  fur- 
ther usefulness,  did  not  the  mosquito  inject  the  secre- 
tion of  its  salivary  glands  into  the  wound.  This  acts 
upon  the  blood  in  such  a  way  as  to  prevent  its  coagu- 
lation. 

Anyone  who  thinks  carefully  can  add  numberless 


98  THE    MEANING    OF    EVOLUTION 

specializations  for  food  getting.  For  instance,  primi- 
tive mammals  have  little  pointed  teeth  which  fit  them 
for  feeding  on  insects.  In  each  of  the  great  order  of 
mammals  a  special  development  of  these  teeth  has 
occurred.  Among  the  rodents  or  gnawing  animals 
the  front  teeth  have  become  long  and  chisel-shaped 
for  nibbling.  The  horse  has  formed  them  for  nip- 
ping, and  his  hind  teeth  for  grinding.  In  the  dog 
the  teeth  near  the  front  have  become  long  for  tearing 
his  flesh  food,  wdiile  his  hind  teeth,  w^orking  with  the 
motion  of  scissors,  cut  it  into  pieces. 

A  second  great  class  of  specialization  is  seen  in 
the  changes  of  habit  that  provide  the  animal  with 
shelter.  The  home  seems  so  necessary  a  part  of  hu- 
man life  that  it  is  almost  impossible  to  think  of  an 
animal  having  nothing  that  in  the  faintest  degree 
could  be  called  a  home.  We  at  least  expect  it  to  have 
some  sheltered  place  in  which  it  passes  most  of  its 
time  and  to  which  it  returns  after  its  wanderings. 
The  great  majority  of  all  animals  have  no  such  home. 
The  place  in  which  we  find  them  to-day  may  not  be 
the  place  in  which  they  will  be  to-morrow.  All  places 
are  alike  to  them.  The  ordinary  conduct  of  their 
daily  life  drives  them  about  in  the  search  for  food. 
Their  attempt  to  escape  from  their  enemies  leads  them 
each  day  into  new  situations,  and  they  may,  and  prob- 
ably do,  have  no  power  to  recognize  the  old  location  if 


ADAPTATION    FOR    THE    INDIVIDUAL  99 

they  return  to  it.  When  we  come  to  the  backboned 
animals  there  is  a  httle  more  tendency  to  a  stationary 
location.  The  sun  fish  may  frequent  the  same  reach 
of  the  stream,  the  trout  may  haunt  the  same  po^l, 
year  after  year,  but  a  great  majority  of  fishes  doubt- 
less move  indiscriminately  up  and  down  the  stream  '-^■' 
or  about  the  lake  or  ocean  and  are  not  found  two 
successive  days  in  the  same  place.  The  same  may  be 
said  of  frogs.  For  a  time  a  particular  frog  may  have 
a  fondness  for  a  special  bend  in  the  stream,  but  it  is 
only  a  temporary  fondness,  I  believe. 

Our  own  need  for  shelter  is  the  prime  motive  in 
leading  us  to  build  a  home,  and  this  necessity  arises 
first  of  all  because  of  our  warm  blood.  What  we  are 
accustomed  to  call  cold-blooded  animals  are  not  truly 
so.  Their  blood  holds  practically  the  temperature  of 
their  surroundings.  As  the  air  or  the  water  in  which 
they  live  grows  warmer  or  colder  the  bodies  of  these 
creatures  alter  with  it.  Consequently  they  are  active 
when  the  temperature  is  high  and  grow  more  slug- 
gish as  the  thermometer  falls.  When  the  day  grows 
distinctly  cold  the  animals  may  go  practically  dor- 
mant. 

Only  the  birds  and  mammals  have  warm  blood,  and 
of  these  the  birds  are  distinctly  the  warmer.  Whereas 
the  temperature  of  the  mammals  runs  from  about 
ninety-eight  to  a  hundred  degrees  Fahrenheit,  that  of 


t\ 


lOO  THE    MEANING    OF    EVOLUTION 

birds  lies  somewhere  between  one  hundred  and  five  de- 
grees and  a  hundred  and  ten.     Creatures  which  are 
warmer  than  their  surroundings  must  have  some  pro- 
tection against  chiUing.     Accordingly  both  mammals 
and  birds  have  clothing.     In  the  case  of  mammals 
the  covering  is  fur,  in  the  case  of  birds  feathers.     In 
some   of  the  tropical  animals  like  the  elephant  and 
rhinoceros,  or  in  man,  who  has  learned  to  protect  him- 
self in  cold  regions  by  making  clothing  for  himself, 
this  hair  is  very  short,  and  except  w^here  serving  for 
ornament  is  quite  scanty,  no  longer  being  of  use  as  a 
protection.     But  the  great  majority  of  all  mammals 
are  well  covered  with  a  dense  coat  of  hair.     In  many 
of  those  living  in  the  colder  regions  there  is  in  reality 
a  double  coat.    The  fur  seal  of  the  Alaskan  Islands  is 
so  provided.     A  set  of  long  hairs  deeply  fastened  in 
the  skin  forms  a  covering,  which  shows  on  looking 
at  the  seal.    Underneath  this  layer,  and  set  but  lightly 
into  the  skin,  is  a  short  coat  of  very  much  finer  hair 
known  as  the  underpelt.    When  the  skin  is  taken  from 
the  seal  It  is  split  by  machinery  into  a  lower  and  an  up- 
per layer.    When  so  split  the  deep-seated  pits  of  the 
long  hairs  are  cut,  and  these  hairs  come  out.    The  fine 
underpelt  thus  laid  bare  is  what  is  commonly  known 
as  sealskin.     Fashion  has  decreed  that  this  must  be 
dyed  a  rich  brow^n,  although  wdien  taken  from  the 
animal  it  is  nearly  mouse  gray. 


ADAPTATION    FOR    THE   INDIVIDUAL  lOI 

The  birds  have  need  for  better  clothing.  To  begin 
with,  their  blood  is  much  warmer,  and  hence  needs 
better  protection  from  outside  cold.  In  addition  such 
of  them  as  fly  high  must  be  prepared  to  stand  great 
variations  in  temperature.  For  these  purposes  birds 
need  a  covering  of  the  finest  type.  This  clothing,  in 
addition,  must  be  extremely  light  because  the  creature 
must  carry  it  into  the  air  in  flight.  All  of  the  requi- 
site conditions  are  thoroughly  met  by  the  feather, 
which  is  the  lightest  and  warmest  clothing  known  to 
man.  If  at  night  we  wish,  regardless  of  expense,  to 
keep  ourselves  warm  with  the  lightest  and  warmest  of 
covering,  we  send  to  the  Arctic  Sea,  and  from  the 
breast  of  the  eider  duck  we  pluck  the  down  which 
lies  between  the  warm  blood  of  the  duck  with  its  tem- 
perature of  one  hundred  and  seven  degrees  and  the 
water  in  which  the  iceberg  floats. 

Young  mammals  and  birds,  before  their  clothing 
has  well  formed,  are  naturally  susceptible  to  cold ;  this 
leads  to  the  first  genuine  approach  to  a  home  among 
animals  lower  than  man.  Birds  lay  their  eggs  long 
before  the  creatures  inside  of  them  are  ready  to 
emerge.  Accordingly  they  have  learned  to  build  nests 
in  which  to  place  these  eggs,  and  to  protect  them 
from  the  outside  air;  meanwhile  the  bird  keeps  the 
eggs  warm  by  close  contact  with  its  own  body.  The 
lowest  of  the  birds  may  lay  their  eggs  simply  on  the 


I02  THE    MEANING    OF    EVOLUTION 

groiincl  wilhuut  any  special  protection.  As  we  rise 
in  the  scale  of  the  bird  world  we  find  nests  provided 
for  the  eggs.  1  hese  nests  become  increasingly  com- 
plex: and  specialized,  until  we  reach  the  oriole's  home 
with  its  wonderfully  woven  mass  of  fiber,  which,  in 
spite  of  its  apparent  looseness,  supports  well  the 
weight  of  the  mother  bird  and  of  her  eggs.  The 
robin,  not  content  with  making  a  woven  basket,  plas- 
ters it  with  clay,  and  makes  an  absolutely  impervious 
nest. 

When  we  remember  that  both  mammals  and  birds 
are  the  modern  descendants  of  cold  and  scaly  reptiles 
of  an  earlier  geological  time,  it  becomes  interesting  to 
compare  their  clothing.  Evidently  in  the  mammals 
hairs  began  to  come  out  between  the  scales.  Gradu- 
ally the  scales  became  fewer  and  the  hairs  more  abun- 
dant until  finally  the  scales  have  all  disappeared,  ex- 
cept those  that  remain  as  the  claws  on  the  toes.  The 
ancestors  of  the  birds,  on  the  other  hand,  boldly  trans- 
formed their  scales  into  feathers. 

Another  need  for  shelter  arises  in  connection  with 
the  approach  of  winter.  This  problem  of  withstand- 
ing the  cold  season  is  complicated  by  the  presence  of 
two  new  factors.  First  and  most  directly,  the  cold 
itself  is  a  distinct  obstacle  to  the  comfort  of  many  of 
these  creatures ;  as  a  secondary  result  of  this  cold,  the 
food  of  many  animals  disappears  entirely  in  winter. 


ADAPTATION    FOR   THE   INDIVIDUAL  I03 

Most  of  our  birds  meet  this  difficulty  by  changing 
their  base  of  operations.  When  the  north  grows  cold 
these  creatures  fly  to  the  south.  Some  of  their  mi- 
grations cover  enormous  stretches  of  country.  Our 
bobolink,  so  well  known  and  loved  by  all  watchers 
of  spring  migrations,  passes  twice  a  year  between  the 
latitude  of  New  York  and  Rio  Janeiro.  One  of  our 
most  careful  students  of  bird  migration  says  that  the 
Golden  Plover  makes,  twice  each  year,  the  long  jour- 
ney from  the  Arctic  shores  of  North  America  to  the 
plains  of  La  Plata. 

Different  fur-covered  animals  have  specialized  to 
meet  the  winter  by  any  one  of  three  different  methods. 
They  may  brave  it  out,  hunting  for  their  food  as  best 
they  can  all  winter  long.  Such  a  course  is  pursued  by 
the  rabbit.  Again  like  the  squirrel,  they  may  store 
large  quantities  of  food  during  the  summer,  and  on 
this  provender  they  may  subsist  during  winter,  re- 
maining for  most  of  the  time  near  their  hiding-places, 
which,  however,  they  may  frequently  leave  upon 
warm  days.  A  third  method  is  less  common,  but  very 
interesting.  The  groundhog  or  woodchuck  is  the 
best-known  example  of  the  group.  It  remains  asleep, 
or,  as  it  is  technically  known,  dormant,  during  the 
winter.  This  stupor  is  more  profound  than  ordinary 
sleep,  and  from  it  these  animals  awaken  with  diffi- 
culty.    It  is  needless  to  remark  that  the  groundhog's 


104  THE    MEANING   OF   EVOLUTION 

behavior  on  the  second  of  FelDruary  has  no  relation 
^vhatever  to  the  weather  we  are  to  have  later  in  the 
season.  This  is  coming  to  be  pretty  generally  under- 
stood. While  the  newspapers  each  year  comment 
upon  the  groundhog  and  his  shadow  upon  that  day, 
year  by  year  the  notice  has  more  of  humor  in  it,  and 
fewer  people  pay  any  attention  to  it. 

As  for  the  backboned  animals  which  are  cold- 
blooded, these  must,  unless  they  are  fish,  give  up  the 
struggle  completely,  bury  themselves  in  out-of-the- 
w^ay  places,  and  go  worse  than  dormant.  They  often 
become  absolutely  cold  and  stiff.  In  the  case  at  least 
of  fish,  it  is  quite  possible  for  them  to  be  frozen  stiff, 
even  to  be  enclosed  in  cakes  of  ice,  and  still  to  recover 
if  the  encasement  is  not  too  long  continued.  But 
the  snakes,  the  turtles,  the  toads,  the  lizards,  all 
are  hidden  beneath  the  ground  waiting  in  abso- 
lutely unconscious  rest  the  return  of  warmer 
weather. 

After  the  need  for  food  and  shelter  comes  the  con- 
tinually recurring  necessity  on  the  part  of  almost 
every  type  of  animal  to  escape  from  the  unwearying 
persecution  of  higher  creatures  which  Avould  feed 
upon  it.  The  whole  creation  is  a  constant  network  of  j 
animals  which  prey  upon  each  other.  It  is  the  fate  of 
a  great  majority  of  all  creatures  to  fall  victim  to  other 
animals  to  whom  they  serve  as  food.    Accordingly  na- 


ADAPTATION    FOR    THE   INDIVIDUAL  1 05 

ttire  has  concocted  many  devices  by  which  she  assists 
her  favored  children  in  escaping  this  relentless  perse- 
cution.    Perhaps  the  most  widespread  means  which 
animals  have  developed  in  order  to  elude  their  ene- 
mies lies  in  the  possession  of  power  to  escape  their 
attention.     Two  different  factors  may  contribute  to 
this  end.    The  first  of  these  consists  in  the  practice  on 
the  part  of  many  animals  of  remaining  absolutely 
quiet  in  time  of  danger.     This  instinct  seems  to  be 
nearly  universal.     The  first  impulse  of  most  animals 
upon  discovering  danger  is  to  remain  absolutely  mo- 
tionless.    The  eye  detects,  with  ease,  objects  in  mo- 
tion.   These  same  objects  might  entirely  escape  atten- 
tion were  they  quiet.     A  mouse  could  remain  in  the 
corner  of  a  room  for  a  long  time  without  attracting 
the  eyes  of  the  occupants  of  the  room.     Let  it  but 
scamper  across  the  corner,  and  at  once  it  is  discov- 
ered.    It  is  quite  conceivable  that  early  animals  were 
divided  in  the  matter;  that  the  impulse  of  some  was  to 
escape  from  danger,  while  others,  frightened  by  the 
presence  of  the  enemy,  remained  absolutely  still.  Each 
plan  has  succeeded.     Those  which,  on  running,  ran 
fast  enough  to  escape  became  the  parents  of  others 
like  themselves,  led  eventually  to  a  line  of  animals  in 
whose  speed  lay  their  safety.    Those,  however,  which 
attempted  to  escape,  and  failed  because  they  were  not 
swift  enough,  had  their  line  cut  off,  and  were  thus 


Io6  THE    MEANING   OF    EVOLUTION 

less  likely  to  be  represented  in  the  following  genera- 
tion. The  constant  result  of  errors  along  this  line 
would  be  to  destroy  the  slow  and  preserve  the  swift, 
and  in  the  course  of  time  it  is  quite  thinkable  that 
only  the  swift  should  remain.  As  the  movements 
grew  more  and  more  keen,  even  the  slower  of  these 
would  pass  out,  thus  tending  always  to  produce  the 
succeeding  generation  from  those  wdio  were  most 
rapid,  and  hence  most  likely  to  transfer  to  their  chil- 
dren a  similar  power. 

But  there  is  another  tendency  of  animals  which 
leads  them  when  frightened  by  their  enemies  to  re- 
main quiet.  If  this  impulse  is  obeyed  thoroughly 
enough,  it  is  easy  to  see  how  the  owner  of  this  habit 
might  entirely  escape  detection  by  his  enemy.  Any 
restless  animal  unable  to  restrain  his  nervous  agita- 
tion naturally  betrays  his  presence  and  is  picked  off. 
The  result  of  evolution  along  this  line  would  be  the 
exact  reverse  of  the  preceding.  Those  that  lay  most 
absolutely  quiet  would  be  the  parents  of  succeeding 
generations,  while  those  who  were  slow  in  coming 
to  rest,  or  were  indifferent  about  remaining  quiet, 
were  picked  off,  and  their  tendency  eliminated  from 
the  future  of  the  species.  In  this  way  many  animals 
have  come  to  keep  entirely  quiet  in  the  presence  of 
danger.  It  is  not  a  sign  of  high  intelligence.  As  a 
matter  of  fact,  it  is  rather  a  stupid  procedure,  so  far 


ADAPTATION    FOR    THE    INDIVIDUAL  I07 

as  the  animal  itself  is  concerned,  but  it  is  a  preserving 
stupidity,  and  many  animals  have  it. 

The  "J^i^^  Bug"  (which  is  not  a  bug,  but  a  beetle, 
and  arrives  in  May)  has  this  interesting  habit  of  keep- 
ing quiet.  If  in  its  flight  it  strikes  the  globe  of  an 
electric  light,  it  falls  at  once  to  the  ground,  and  re- 
mains perfectly  quiet  for  a  time.  After  a  short  inter- 
val it  recovers  and  starts  out  to  regain  its  previous  ac- 
tivity. But  this  recovery  is  by  slow  stages,  and  the 
whole  procedure  on  its  part  looks  exceedingly  stupid. 

The  little  snake  with  flattened  and  expanded  head, 
known  as  the  blowing  viper,  or  puff  adder,  is  one  of 
the  most  amusing  representatives  of  the  tendency  to 
"play  dead"  that  could  well  be  found.  If  you  strike 
him  the  faintest  blow  with  the  lightest  stick,  he  at 
once  goes  into  apparent  convulsions,  in  which  he 
seems  to  suffer  the  greatest  agony.  Then,  throwing 
himself  upon  his  back,  he,  to  all  appearances,  yields 
up  the  ghost.  If,  however,  you  retire  but  a  slight  dis- 
tance and  keep  your  eye  upon  him,  you  find  that  his 
ghost  returns  after  a  comparatively  short  absence,  and 
he  slinks  away  out  of  danger.  This  is  the  most  effec- 
tive exhibition  of  this  kind  with  which  I  am  ac- 
quainted. 

As  for  the  habit  of  "playing  'possum"  on  the  part 
of  our  opossum,  the  trick  would  seem  to  be  particu- 
larly inane.     The  truth  of  the  matter  is,  what  is  at- 


loS  THE    MEANING    OF    EVOLUTION 

tributcd  to  an  unusual  brilliancy  on  the  part  of  the 
creature  is  positively  unusual  witlessness.    The  animal 
has  an  exceedingly  small  brain,  as  compared  with  that 
of  a  dog  of  similar  size,  and  to  anyone  who  knows 
brains  at  all  this  particular  organ  would  not  be  looked 
upon  as  furnishing  its  owner  much  ability.     The  fact 
is  that  the  opossum  has  exceedingly  small  wit,  and 
this  little  deserts  it  in  an  emergency,  as  a  result  of 
which  he  grows  helpless  and  motionless.    This  is  often 
supposed  to  indicate  great  wisdom.     There  may  be 
wisdom  in  it,  but  it  is  the  wisdom  that  lies  back  of  all 
nature.    It  certainly  is  not  the  wisdom  of  the  opossum. 
Man  himself  possesses  to  a  marked  degree  this  im- 
pulse to  keep  quiet  in  danger.     The  man  from  the 
country    who    is    visiting    the    large    city,    suddenly 
startled  by  the  "honk"   of  the  auto  horn,  finds  his 
power  of  movement  promptly  arrested,  and  he  is  not 
unlikely  to  be  struck  and  injured  by  the  machine  from 
which  the  city  dweller  would  easily  escape.     This  is 
not  particularly  to  the  credit  of  the  city  dweller,  who, 
when    in    the    country,    may    find    himself    similarly 
startled  by  the  sudden  appearance  of  the  calf,  the  pig, 
or  the  sheep.     The  bull,  which  a  country  boy,  accus- 
tomed to  him  from  childhood,  will  drive  with  a  willow 
switch,  is  a  source  of  terrified  concern  to  the  city  man. 
While  the  trick  of  keeping  quiet  serves  many  an 
animal  in  time  of  danger,  there  is  another  device  for 


ADAPTATION    FOR    THE   INDIVIDUAL  lOQ 

escaping  attention,  far  more  common  and  widespread 
throughout  the  animal  world.  The  eye  does  not  eas- 
ily see  an  object  if  it  is  colored  like  the  background 
against  which  it  stands.  A  host  of  animals  find  their 
main  safety  in  being  indistinguishable  in  color  from 
the  surface  on  which  they  live.  There  are  many  biolo- 
gists who  seriously  question  whether  protective  colora- 
tion, as  Darwin  called  it,  is  as  effective  as  he  believed 
it.  In  some  quarters  it  is  the  present  fashion  to  doubt 
protective  coloration  entirely.  No  one  has  yet  shown 
any  principles  which  will  better  explain  the  great  color 
scheme  of  the  animal  world,  and  until  such  explana- 
tion is  forthcoming  I  believe  it  will  not  be  wise  for  us 
to  discard  the  idea  of  protective  coloration.  No  doubt 
it  has  been  overworked  by  enthusiastic  believers  in  its 
efficiency.  At  the  same  time,  to  overlook  it  com- 
pletely, is,  I  believe,  to  make  a  greater  error.  I  have 
little  doubt  that  when  the  broader  explanation  comes, 
which  will  satisfactorily  explain  the  color  scheme  of 
the  animal  world,  the  idea  of  protective  coloration 
will  be  found,  not  so  much  to  have  been  wrong,  as  to 
have  been  but  partial.  It  will  be  included  under  the 
broader  principle  which  takes  its  place  and  will  not  be 
supplanted  by  it. 

The  idea  of  protective  coloration  is  that  very  many 
animals  have  ordinarily  come  to  be  colored  like  the 
background   on   which   they   live.     The  process   has 


no  THE    MEANING    OF   EVOLUTION 

taken  many  generations,  and  is  very  slow,  but  is  none 
the  less  sure  in  the  end.  In  most  cases  the  animal  is 
probably  entirely  unconscious  of  this  point  in  its 
favor,  and  usually  it  does  nothing  to  assist  the  decep- 
tion. The  result  is  none  the  less  effective  because  the 
animals  themselves  are  unconscious  of  the  process. 
The  cabbage  worm  is  green  in  color  like  the  cabbage. 
This  does  not  mean  that  it  got  green  by  eating  cab- 
bage or  by  longing  for  greennesses.  Through  long 
years  the  enemies  of  the  cabbage  Avorm  have  been 
picking  it  off  the  plants  on  which  it  fed.  This  does 
not  imply  that  cabbages  as  we  know  them  are  very 
old,  but  cabbage  worms  doubtless  ate  the  leaves  of  the 
sea-kale  long  before  man  had  cultivated  it  into  cab- 
bage. During  all  these  years  the  enemies  of  the  cater- 
pillars, generally  in  the  shape  of  birds,  have  been  as- 
siduously gathering  them  up. 

When  we  see  how  much  the  various  members  of 
the  same  human  family  may  differ  in  complexion,  how 
much  the  various  pigs  in  the  same  litter  may  differ 
in  size  and  in  coloration,  it  is  easy  to  understand  that 
among  these  caterpillars  which  have  eaten  the  cabbage 
there  must  have  been  considerable  color  variations.  I 
do  not  imagine  for  a  moment  that  the  birds  had  any 
preference  for  any  particular  color  in  their  cabbage 
worms.  .  They  took  every  caterpillar  they  saw,  but 
they  naturally  first  saw  those  that  were  least  like  the 


ADAPTATION    FOR    THE   INDIVIDUAL  III 

background  on  which  they  Hved.  The  only  caterpillar 
which  was  effectively  hidden  from  his  enemy  was  the 
one  that  was  indistinguishable  on  the  leaf."! If  it  es- 
caped in  this  way,  the  probabilities  are  that  it  would 
produce  young  which  would  be  at  least  a  little  more 
likely  to  be  green  in  color  than  the  progeny  of  its 
darker-colored  brothers  and  sisters.  By  this  contin- 
ued process  the  birds  steadily  weed  out  the  darker- 

1 — 
colored  specimens,    rihere  would  result,  in  the  course 

of  time,  a  race  of  caterpillars,  whose  ancestors  for  so 
many  generations  back  had  been  light  green  in  color, 
that  there  is  little  likelihood  of  any  of  the  older  and 
darker  forms  turning  up  again.  In  the  course  of  time 
all  dark  tendencies  will  have  disappeared  from  the 
family  and  practically  all  of  the  group  will  be  light 
green,  f  Any  sport  or  variation  in  the  shape  of  greater 
conspicuousness  would  fall  a  quick  prey  to  the  enemy 
and  its  line  be  cut  off  forever. 

The  same  sort  of  activity  has  resulted  in  the  pe- 
culiar green  color  of  the  katydid.  This  creature  lives 
chiefly  upon  the  leaves  of  trees  and  shrubs.  This  in- 
sect is  so  large  that,  even  though  it  is  leaf-like  in  color, 
it  might  still  be  conspicuous.  As  a  result  those  katy- 
dids whose  wings  were  most  like  leaves  in  form  were 
least  likely  to  be  picked  up  by  the  passing  bird.  This 
sort  of  protective  appearance  is  intensified  by  exactly 
the  same  means  as  that  which  brought  about  protec- 


112  THE    MEANING    OF    EVOLUTION 

tive  coloration.  The  katydid  least  leaflikc  in  appear- 
ance was  eaten  first.  Thus  those  most  leailike  remain 
until  the  last,  and  are  most  likely  to  produce  young. 
Again,  it  was  not  the  fact  that  they  lived  among 
leaves  which  made  them  look  leaflike,  but  it  is  because 
they  look  like  leaves  that  they  escaped  being  devoured. 

The  katydid  has  materially  assisted  in  its  own  pres- 
ervation by  being  active  chiefly  at  night.  In  the  day- 
time it  keeps  comparatively  quiet.  Thus  seated  upon 
a  twig,  especially  if  hidden  among  the  leaves,  it  is  al- 
most unnoticeable.  At  night,  however,  it  moves  about 
more  freely,  seeking  its  food  and  eventually  its  mate. 
At  such  times  it  becomes  distinctly  more  conspicuous 
because  its  wings  are  steadily  fluttering.  The  hind 
wings  are  filmy  and  are  very  light  green.  The  crea- 
ture looks  most  ghost-like  as  it  flies  through  the  even- 
ing: air. 

A  very  similar  history  lies  back  of  the  coloring  of 
the  ordinary  toad.  Though  descended  from  the  frog, 
and  originally  a  creature  of  the  water,  the  toad  has 
long  since  adapted  itself  to  live  upon  the  dry  ground. 
It  still  produces  its  young  in  the  water  as  it  did  when 
a  frog.  Whereas  the  childhood  of  the  frog,  that  is, 
its  tadpole  stage,  is  very  long  and  it  assumes  its  adult 
form  comparatively  late,  just  the  reverse  is  the  case 
of  the  toad.  The  young  hasten  through  their  tadpole 
stage  within  a  few  weeks,  and  assume  the  shape  of 


ADAPTATION    FOR    THE   INDIVIDUAL  II3 

the  parent  toad  when  about  big  enough  to  cover  your 
little  fingernail.  Now  they  leave  the  water  and  seek 
dry  land.  Naturally  they  make  the  change  when  the 
land  is  damp,  that  is,  after  a  warm  spring  rain.  Peo- 
ple seeing  these  multitudes  of  little  toads  hopping 
around  over  a  bare  spot  of  ground,  and  remembering 
the  rain  of  the  night  before,  insist  that  it  has  rained 
toads.  Of  course  it  never  rains  down  anything  which 
cannot  evaporate  up.  The  stories  of  showers  of  toads 
and  of  earth  worms,  with  an  occasional  fish,  or  even 
creatures  of  larger  size,  are  all  pure  myths.  There 
are  conceivable  tornadoes  after  which  there  might  be 
a  shower  of  such  creatures,  but  at  such  a  time  it  is 
likely  also  to  rain  barn  roofs  and  buggies.  You  may 
be  sure  that  toads  which  come  down  in  the  rain  are 
dead  after  they  strike  the  ground. 

The  little  toads  started  out,  perhaps  a  hundred  at  a 
time,  from  the  small  pool  in  which  their  eggs  were 
laid.  These  creatures  find  dragons  on  every  side. 
The  gartersnake  comes  along  and  gets  his  first  toll; 
the  heron  follows  him  and  takes  such  as  catch  his 
hungry  eye ;  the  turkey  gobbles  up  his  from  what  are 
left.  By  the  time  the  toad-eating  creatures  in  the 
neighborhood  have  taken  such  as  they  found,  there 
are  very  few  remaining.  These  doubtless  have  been 
left  for  a  very  good  reason,  generally  because  they 
were  not  noticed.    This  was  because  they  looked  like 


Jl\.  THE    MEANING    OF    EVOLUTION 

the  ground  on  which  they  sat,  and  because  they  kept 
perfectly  quiet  while  the  enemy  moved  about.  This 
process  has  gone  on  so  long  that  the  toad  has  come 
to  be  astonishingly  well  protected  by  its  resemblance 
to  the  ground.  This  likeness  it  intensifies  by  its  inter- 
esting habit  not  only  of  keeping  entirely  quiet,  but  of 
dropping  its  nose  to  the  ground,  instead  of  sitting 
high  on  its  front  legs,  as  it  does  when  not  in  danger. 

I  have  noticed  that  if  a  snake  and  a  toad  be  placed 
in  the  same  cage,  when  the  snake  approaches  to  cap- 
ture the  toad  the  toad  drops  into  a  squatting  position, 
and  is  very  likely  to  blow  himself  up  until  he  is 
rounder  in  outline  than  he  was  before.  Whether  this 
is  a  deceptive  trick  which  makes  him  the  more  resem- 
ble a  stone  is  more  than  I  can  say.  I  do  not  remem- 
ber having  seen  our  eastern  toad  do  it.  I  have  seen 
it  happen  a  number  of  times  in  the  laboratory  of  a 
Colorado  naturalist,  and  it  is  quite  possible  that  in  the 
open  country  more  sparsely  covered  with  vegetation 
than  is  our  ground  in  the  east  this  inllating  device 
may  serve  the  toad  more  effectually  than  if  it  kept  its 
own  outline. 

Even  among  creatures  far  more  active  than  the 
toad  and  the  katydid  an  inconspicuous  color  must  cer- 
tainly result  in  distinctly  better  protection.  Everyone 
knows  the  jay  and  the  cardinal  when  first  he  has  seen 
them,  if  only  he  has  a  slight  acquaintance  with  their 


ADAPTATION    FOR    THE   INDIVIDUAL  II5 

pictures.  They  are  so  conspicuous  that  we  recognize 
them  at  once.  More  common  in  my  region  than  the 
jay  or  the  cardinal  is  the  red-eyed  vireo.  This  crea- 
ture moves  industriously  in  and  out  among  the  leaves 
of  our  trees.  It  is  persistently  in  motion,  is  nearly 
constant  in  song,  and  is  a  bird  of  fair  size,  being 
larger  than  our  English  sparrow,  though  smaller  than 
a  robin.  Many  a  nature  lover  will  recognize  twenty- 
five  or  thirty  birds  at  sight  without  any  difficulty,  and 
not  know  the  vireo.  Yet  the  vireo  is  more  common 
than  two-thirds  of  the  birds  he  knows.  There  can  be 
but  one  reason  for  this;  the  bird  is  inconspicuous. 
The  olive-green  of  its  back,  with  its  light  under  parts, 
serves  to  hide  it  completely  amid  the  foliage.  Even 
the  bird-lover  learns  to  find  it  first  by  its  jerky  song, 
and  then  by  watching  for  its  movements  among  the 
leaves. 

One  aspect  of  protective  coloration  has  been 
brought  to  our  attention  by  the  artist,  Mr.  Abbott  N. 
Thayer.  He  first  clearly  explained  why  it  is  that  ani- 
mals are  usually  so  much  lighter  on  the  under  side  than 
they  are  upon  the  upper.  Mr.  Thayer  proves  his  posi- 
tion by  taking  some  ordinary  cobblestones  and  paint- 
ing one  of  them  a  uniform  color  and  placing  it  upon 
a  board  painted  the  same  color.  One  would  think  the 
stone  would  be  inconspicuous;  as  a  matter  of  fact,  is 
quite  easily  seen.     The  underside  of  the  stone,  turned 


Il6  THE    MEANING    OF    EVOLUTION 

away  from  the  light,  is  so  shaded  as  to  mark  a  dis- 
tinct boundary  between  the  stone  and  the  board.  An- 
other cobblestone  was  colored  on  its  upper  side  like 
the  board,  but  the  color  faded  into  a  lighter  and 
lighter  tint  until  the  bottom  of  the  stone  was  nearly 
white.  This  stone,  placed  upon  the  board,  was  at 
a  short  distance  nearly  invisible.  In  other  words,  al- 
though the  pigment  was  actually  lighter  on  the  under 
side,  it  was  so  much  less  intensely  illuminated,  that 
the  result  was  the  same  in  tint  as  the  other  side  un- 
der the  clear  sharp  light  of  the  sky. 

Many  a  person,  looking  down  into  the  water  from 
a  bridge,  sees  nothing  whatever  of  the  fish  in  the  wa- 
ter below,  because  their  backs  are  exactly  like  the 
bottom  of  the  stream.  Suddenly  one  of  the  fish,  by  a 
quick  movement,  turns  its  lighter  under  side  over  in 
such  a  way  that  it  is  clearly  illuminated  from  the  sky. 
Immediately  a  flash  as  of  silver  strikes  the  eye  of  the 
onlooker  and  makes  him  aware  of  the  presence  of  the 
fish  which  had  previously  been  undetected.  If  ren- 
dered thus  suspicious,  the  observer  will  carefully  ex- 
amine the  bottom  of  the  water,  he  may  quite  likely 
find  dozens  of  fish  which  had  previously  escaped  his 
attention. 

Nature  is  very  versatile.  So  many  of  her  ap- 
parently chance  ventures  have  proved  successful  that 
she  has  retained  many  devices  by  which  her  children 


ADAPTATION    FOR    THE   INDIVIDUAL  II 7 

may  be  safe.  One  of  these,  which  is  doubtless  often 
quite  effective  and  may  serve  to  save  an  animal's  life, 
is  that  of  being  able  to  emit  an  odor  so  nauseating  as 
to  offend  the  enemy's  sense  of  smell,  and  doubtless 
remove  the  keen  edge  of  his  appetite.  It  is  not  un- 
common among  the  group  of  insects  properly  known 
as  bugs  to  possess  an  exceedingly  unpleasant  odor. 
Anyone  who  has  handled  a  squash  bug  will  know  ex- 
actly what  I  mean,  and  there  are  other  members  of 
the  group  not  so  common  as  the  squash  bug,  which, 
at  least  to  the  human  nose,  are  distinctly  offensive. 
Some  of  the  beetles  also  save  themselves  by  this  de- 
vice. 

One  of  the  most  interesting  developments  of  this 
peculiarity  is  found  in  the  case  of  the  common  skunk. 
This  creature  has  in  each  groin  a  gland  capable  of  se- 
creting a  highly  offensive  fluid.  Ordinarily  this 
liquid  is  kept  safely  within  its  sac,  and  for  a  long  time 
none  of  it  may  escape.  When  closely  cornered,  the 
skunk  will  turn  its  tail  toward  the  enemy  and  with 
a  quiver  and  a  flip  of  his  tail  it  can  guide  the  openings 
of  two  little  tubes  that  come  out  along  the  root  of  the 
tail  in  such  fashion  as  to  eject  the  fluid  in  a  fine  and 
foul-smelling  stream  against  the  animal  from  w^hich 
the  skunk  would  escape.  Once  fairly  hit  by  this  fluid, 
I  imagine  most  animals  will  drop  the  skunk.  A  dog 
surely  will,  and  will  hate  himself   for  having  made 


Il8  THE    MEANING    OF    EVOLUTION 

the  attempt  to  capture  anything  which  must  be  so 
ignominiously  allowed  to  escape.  If  one's  clothing  is 
well  saturated  with  it,  it  is  nearly  useless  to  hope  to 
remove  the  odor.  A  dog  will  carry  the  smell  for  sev- 
eral weeks.  For  a  long  time  it  will  be  so  strong  as 
to  make  him  an  unfit  denizen  of  the  house.  Even 
swimming  in  deep  water  does  not  remove  it.  After 
two  weeks,  although  he  may  seem  to  be  practically 
free  from  the  odor,  a  light  rain  will  bring  it  all  out 
again  and  make  him  nearly  as  offensive  as  before. 

Not  as  prompt  in  its  action,  but  in  the  end  nearly 
as  effective,  is  the  protective  device  which  the  toad 
sometimes  uses  to  his  distinct  advantage.  May  I 
be  pardoned  a  personal  account  of  this  particular 
feature.  It  was  my  good  fortune  to  be  for  a  short 
time  a  student  in  a  class  taught  by  Edward  Drinker 
Cope,  one  of  the  most  brilliant  of  our  American  bi- 
ologists. Prof.  Cope  mentioned  in  class  the  fact  that 
the  Batrachians  (the  group  to  which  the  toad  be- 
longs) have  in  many  cases  the  power  to  emit  from 
their  skin  a  fluid  which  is  sufficiently  nauseous  to  de- 
ter an  animal  from  eating  the  creature  that  secretes 
it.  Upon  such  authority  as  this,  I  had  no  hesitancy 
whatever  in  repeating  Cope's  statement.  One  morn- 
ing I  had  a  class  in  the  field  studying  the  ground  ivy, 
whose  dainty  blue  flowers  were  lifting  themselves  out 
of  the  dewy  grass.     While  we  were  thus  engaged,  a 


ADAPTATION    FOR    THE    INDIVIDUAL  II9 

toad  joined  the  circle.  He  came  out  of  his  dewy  re- 
treat clean  and  fresh  from  his  morning  bath.  I  took 
him  in  my  hands,  and  made  him  the  subject  of  an  im- 
mediate lesson.  I  showed  to  my  pupils  his  eyes  and 
his  interesting  method  of  handling  them,  his  tongue 
and  its  strange  insertion;  showed  them  how  to  look 
into  his  mouth  and  look  up  his  ears  to  his  ear  drums, 
and  pointed  out  many  other  interesting  facts.  Then 
I  told  them  how  Cope  had  said  that  the  toad  had 
power  to  emit  from  its  skin  a  fluid  so  nauseous  that 
many  an  animal  hesitates  to  eat  it.  This  is  the  first 
peculiarity  I  had  mentioned  which  I  had  not  myself 
observed,  and  a  scientific  qualm  came  over  my  con- 
science. Why  had  I  never  verified  this  statement 
which  I  had  so  frequently  repeated?  On  the  impulse 
of  the  moment,  with  the  bright,  clean  skin  of  the 
creature  fresh  from  the  dewy  grass,  making  it  less 
than  usually  repulsive,  I  ran  my  tongue  up  its  back 
only  to  find  that  it  had  no  taste  whatever.  I  was  of 
course  surprised,  but  I  was  not  foolish  enough  to 
deny,  as  the  result  of  one  observation,  the  statement 
of  a  good  scientist.  The  observation,  moreover,  was 
one  which  I  naturally  did  not  care  to  repeat  with  any 
frequency.  Of  one  thing  I  was  sure,  toads  do  not  al- 
ways have  an  unpleasant  taste. 

A  year  later  I  had  a  class  down  by  the  side  of  a 
neighboring  pond.     The  pool  was  not  an  attractive 


'I20  THE    MEANING    OF    EVOLUTION 

one,  and  I  had  picked  from  it  a  more  than  commonly 
unappetizing-  looking  toad,  which  proved  to  be  a 
mother  which  had  not  yet  laid  her  eggs.  As  I  held 
her  in  my  hands  and  exhibited  her  various  points  to 
my  pupils,  I  told  them  of  Prof.  Cope's  statement.  I 
also  told  them  of  my  unsuccessful  attempt  the  previ- 
ous year  to  verify  the  statement.  I  added,  however, 
that  I  would  not  repeat  this  experiment  on  this  un- 
appetizing specimen.  Hereupon  the  toad  not  only 
exuded,  but  squirted,  from  a  gland  over  her  left 
shoulder  blade  a  fluid,  milky-like  in  appearance,  and 
forming  a  jet  as  thin  as  a  needle,  but  ejected  with 
force  enough  to  strike  my  face,  which  was  at  least 
fifteen  inches  away.  I  moistened  my  finger  on  my 
tongue,  lifted  the  fluid  from  my  cheek,  and  tasted  it. 
Cope  was  right.  A  toad  can  exude  a  most  nauseous 
fluid.  Horsechestnuts  extracted  and  distilled  might 
possibly  provide  something  as  bitter.  Why  did  I  not 
find  this  in  the  preceding  case  ?  I  have  too  few  obser- 
vations on  which  to  base  a  conclusion,  but  I  have  a 
suspicion  as  to  the  reason.  In  the  case  of  the  toad 
which  spurted  the  fluid  in  my  face,  we  had  a  creature 
with  whose  life  were  tied  up  the  lives  of  her  many 
offspring,  to  be  produced  from  the  eggs  she  was 
so  soon  to  lay.  Under  conditions  like  these,  na- 
ture is  more  than  commonly  careful  of  her  children. 
Whether  this  be  the  reason  or  not,  toads  do  not  al- 


ADAPTATION    FOR    THE   INDIVIDUAL  121 

ways  have  an  unpleasant  taste,  but  when  they  do  it 
certainly  is  most  unpleasant. 

There  remains  to  be  considered  the  most  effective 
plan  yet  mentioned  of  escaping  the  enemy,  and  that 
is  of  really  escaping.  In  all  the  devices  we  have  con- 
sidered thus  far  the  enemy  is  eluded.  When  the 
creature  lies  quiet,  or  finds  safety  in  its  protective 
coloration,  or  in  its  bad  taste,  or  unpleasant  odor,  it 
still  remains  in  the  presence  of  the  enemy.  A  more 
progressive  plan  altogether  is  to  escape  the  enemy 
by  flight.  The  great  advantage  of  this  plan  lies  in 
the  fact  that  the  acquisition  is  valuable  for  every  pur- 
pose. The  creature  then  can  escape  the  enemy,  can 
range  widely  for  food  or  for  a  mate.  This  gives  it  an 
enormous  advantage  in  the  struggle  for  life.  The 
power  to  fly,  in  insects,  was  doubtless  originally 
gained  in  the  attempt  to  escape  the  enemy.  Among 
many  of  the  lower  animals  it  is  nearly  the  only  pur- 
pose that  flying  serves.  Later  on  it  enables  the  ani- 
mal to  pass  from  one  food  locality  to  another.  In  a 
few  creatures  it  plays  an  effective  part  during  the 
mating  season.  These  last  are  probably  both  derived 
powers,  and  the  original  function  was  that  of  escape 
from  the  enemy.  The  grasshopper  has  grown  its  long 
legs  to  serve  him  for  safety,  and  through  them  it  is 
helped  along,  moving  about  chiefly  by  leaps  when  it 
v/ishes  to  go  any  material  distance.    It  is  only  toward 


122  THE    MEANING    OF    EVOLUTION 

the  A'cry  end  of  its  life  that  the  grasshopper  has  wings, 
and  then  they  serve  probably  to  aid  in  the  search  for 
a  mate.  Among  the  birds  Right  began  simply  in  sail- 
ing out  of  the  trees,  into  which  the  creature,  still  half 
lizard,  had  crept  to  escape  its  enemy.  The  earliest 
bird  known  to  us  had  comparatively  insignificant 
wn'ngs.  There  was  really  more  support  in  its  tail  than 
in  its  wings,  and  this  would  distinctly  indicate  that  it 
glided  more  than  it  Hew.  It  had  claws  also  upon  its 
wnngs,  and  it  was  probably  the  case  that  this  creature 
crept  into  the  trees,  at  least  in  its  earliest  forms,  and 
sailed  down  in  a  manner  not  unlike  that  employed 
to-day  by  the  flying  squirrel.  From  such  simple  be- 
ginnings came  the  wonderful  power  of  flight  in  the 
birds. 

Among  mammals  the  attempt  to  escape  from  the 
enemy  has  led  to  an  interesting  development,  which 
will  be  more  fully  explained  in  a  later  section  when  we 
speak  of  the  history  of  the  horse.  The  early  mam- 
mals walked  flat-footed,  as  we  do  on  our  feet  and  as 
the  raccoon  and  the  bear  do  on  theirs.  Gradually, 
however,  as  their  enemies  became  more  fierce  and  bet- 
ter able  to  injure  the  larger  mammals,  the  latter 
gained  in  power  of  flight,  and  this  gain  consisted  first 
in  rising  from  the  toes,  lifting  the  heels  completely 
off  the  ground.  At  the  same  time  the  leg  and  foot 
were  gradually  lengthened.     Doubtless  in  this  way  the 


ADAPTATION    FOR    THE   INDIVIDUAL  1 23 

fleet  animals,  like  the  deer,  the  horse  and  the  giraffe, 
first  came  by  their  long  legs.  Constant  elimination  of 
the  short-legged  ones,  by  the  pursuing  enemy,  resulted 
in  the  selection  of  the  long-limbed  ones  for  breeding 
purposes,  and  hence  to  the  ultimate  elongation  of  the 
legs  of  the  species. 

The  method  of  escape  from  the  enemy  involves 
cowardice.  "He  who  fights  and  runs  away  may  live 
to  fight  another  day,"  and  so  it  may  be  the  part  of 
wisdom  in  the  weak  creature  to  escape  from  his 
enemy  by  flight.  It  is  a  far  more  estimable  process, 
from  our  standpoint  at  least,  to  stand  against  the  on- 
slaught of  the  enemy  and  beat  him  upon  his  own 
ground.  This  end  is  secured  in  many  animals  by  ac- 
quiring horns  or  by  lengthening  certain  of  the  teeth. 
The  horn  is  a  very  ancient  instrument  of  defense. 
When  the  reptiles  ruled  the  land  horns  were  not  un- 
common. They  consisted  in  those  days  of  hardened 
scales,  which  lengthened  and  fastened  themselves  over 
a  core  of  bone.  Such  an  old-fashioned  instrument, 
sometimes  made  of  newer  materials,  still  remains  the 
defense  of  a  number  of  animals.  The  rhinoceros  has 
upon  his  nose  a  lengthened  projection,  which  is  what 
might  not  improperly  be  called  hair  glued  into  a  cone. 
This  enormous  horn  is  a  frightful  weapon,  both  of 
offense  and  defense,  and,  when  backed  by  the  terrible 
weight  of  the  body  of  the  rhinoceros,  it  can  do  as 


124  THE    MEANING    OF    EVOLUTION 

deadly  work  as  almost  any  instrument  of  destruction 
known  to  animals  below  the  grade  of  man.  But,  after 
all,  this  is  an  old-fashioned  method,  and  the  rhinoceros 
is  a  relic. 

Among  the  carnivorous  animals  the  teeth,  which 
were  developed  first  chiefly  for  the  tearing  of  flesh  in 
its  consumption,  became  effective  for  their  courageous 
owners.  Because  these  tearing  teeth  are  well  devel- 
oped in  the  dog  they  have  come  to  be  known  as  canine 
teeth.  Usually  where  an  animal  can  use  its  teeth  ef- 
fectively for  ofYense  or  defense,  it  is  the  canine  teeth 
that  are  thus  modified.  The  cat  has  developed  them 
better  than  the  dog,  and  one  of  the  cats  of  a  bygone 
geological  period  had  canine  teeth  so  magnificently 
enlarged  and  so  sharp  at  the  back  as  to  give  this 
frightful  creature  the  name  of  the  saber-toothed  tiger. 
The  long  teeth  in  the  upper  jaws  of  the  elephant,  com- 
monly known  as  tusks,  are  not  canine  teeth.  The  ele- 
phant has  completely  lost  his  canines.  His  tusks  are 
his  incisors,  and  they  have  developed  as  have  almost 
no  other  teeth  in  the  mammals. 

These  are  only  a  few  of  the  numberless  devices  na- 
ture has  evolved  for  furthering  the  success  of  her  chil- 
dren. There  are  so  many  others  that  to  many  of  us 
they  form  almost  the  chief  point  of  interest  in  our 
study  of  a  new  animal,  or  our  closer  observation  of  an 
old  friend. 


CHAPTER  V 

Adaptation  for  the  Species 

The  strife,  as  we  have  described  it  thus  far,  is  a 
purely  selfish  struggle.  Every  point  gained  is  a  point 
favorable  to  the  welfare  of  the  individual  animal.  But 
nature  is.  uncommonly  careless  of  the  individual  unless 
the  advantage  gained  is  also  of  use  to  the  species  as  a 
whole.  Very  often  the  life  of  an  animal  ceases  when 
provision  has  been  made  for  its  young.  The  male 
garden  spider  may  have  a  long  and  dangerous  court- 
ship, in  which  the  uncertain  temper  of  his  ladylove 
may  lead  her  to  bite  off  four  or  five  of  his  eight  legs. 
But  her  ingratitude  is  not  yet  complete.  He  may  have 
barely  accomplished  his  desperate  purpose  of  fertiliz- 
ing her  eggs  at  all  hazards,  when  she  ends  the  process 
by  eating  him.  The  male  bumblebee  fertilizes  the  fe- 
male in  the  late  summer  and  then  dies.  She  does  not 
lay  her  eggs  before  the  next  season.  So  it  happens 
that  no  bumblebee  ever  sees  its  own  father,  and  no 
father  bumblebee  ever  sees  his  own  children.  In  the 
honey  bee  the  male,  which  has  been  fortunate  enough 
to   fertilize  the  queen,  pays  for  his  honor  by  death 

125 


126  THE    MEANING    OF    EVOLUTION 

within  the  hour.  Superfluous  bachelors,  among  the 
honey  bees,  when  the  Ijridal  season  has  passed,  are 
driven  from  the  hive  to  die  of  starvation. 

An  animal  need  not  always  be  successful  himself, 
but  it  is  more  essential  that  he  hand  down  his  success- 
ful traits  to  those  who  come  after  him.  It  is  more 
important  for  the  future  generation  that  an  animal 
should  have  had  it  in  him  to  do  great  things,  though 
he  himself  really  have  never  done  them,  than  that  he 
should  have  learned  to  do  great  things  on  a  meager 
original  endowment.  Not  what  an  animal  accom- 
plishes is  important  to  his  children,  but  what  he  has 
it  in  him  to  accomplish.  Accordingly  Nature  is  full  of 
devices  by  which  those  who  have  proved  their  original 
endowment  by  winning  out  in  the  struggle  shall  hand 
on  this  endowment  to  a  subsequent  generation.  In 
other  words,  Nature  is  anxious  that  they  may  suc- 
cessfully mate.  Here  we  are  again  on  distinctly  de- 
batable ground.  Darwin  himself  believed  thoroughly 
in  what  he  called  sexual  selection.  It  is  the  essence 
of  this  idea  that  the  males  and  females  have  grown 
unlike,  more  technically  have  developed  secondary  sex- 
ual characters,  through  the  choice  of  the  mating  pair. 
It  would  usually  be  the  more  serious  loss  if  accident 
should  come  to  the  female,  for  she  may  carry  fertil- 
ized eggs  for  some  time.  Hence,  if  both  sexes  may 
not  become  attractive,  it  is  usually  the  male  that  de- 


ADAPTATION    FOR    THE    SPECIES  1 27 

velops  fine  colors,  ornamental  appendages  or  a  capti- 
vating voice. 

An  interesting  reversal  of  this  process  has  taken 
place  in  civilized  man.  His  more  savage  ancestor 
adorned  himself  more  lavishly  than  he  permitted  his 
mate  to  do.  With  the  advance  of  civilization  man  has 
undertaken  to  defend  his  own  mate  most  valorously. 
The  result  is  it  is  safe  for  her  to  be  beautiful.  Under 
these  circumstances,  however,  it  is  more  necessary  to 
her  w^elfare  that  her  consort  be  vigorous  rather  than 
that  he  be  handome.  Hence  in  the  human  species 
beauty  has  become  the  prerogative  of  the  woman,  and 
this  is  increasingly  the  case  the  higher  the  civilization. 
Whether  woman  suffrage  and  self-support  will  reverse 
this  process  remains  to  be  seen.  There  are  indications 
that  point  that  way. 

There  are  many  biologists  who  are  at  present  ex- 
pressing serious  doubt  as  to  the  validity  of  sexual  se- 
lection. As  in  the  previous  cases  of  protective  colora- 
tion, I  believe  it  will  be  wise  for  us  to  retain,  even 
though  with  an  interrogation  point  behind  it,  the  idea 
of  sexual  selection  until  such  time  as  those  who  ob- 
ject to  it  have  furnished  us  with  another  theory  which 
will  more  nearly  account  for  the  observed  facts. 
While  entirely  conscious  of  the  possibility  that  there 
is  a  wxak  spot  in  the  theory,  we  will  still  tentatively 
hold   to   sexual   selection.      The   fact   that  beauty   in 


128  THE    MEANING    OF    EVOLUTION 

women  is  so  intensely  attractive  to  man,  and  that 
vicror  and  manliness  in  man  arc  so  attractive  to 
women,  leads  us  to  infer  that  among  the  lower  ani- 
mals, although  of  course  in  a  vastly  less  degree,  vigor 
and  beauty  are  also  attractive.  The  weakest  point  of 
the  position  lies  in  the  fact  that  it  probably  presup- 
poses a  higher  degree  of  capacity  for  appreciation  on 
the  part  of  lower  animals  than  they  possess.  Those 
who  deny  the  truth  of  the  theory  laugh  at  the  idea 
that  a  butterfly  can  see  clearly  enough  and  care  enough 
for  what  it  sees  to  notice  whether  its  mate  has  wings 
of  one  type  or  of  another.  The  size,  number  and 
position  of  the  spots  on  the  wings  of  many  butterflies 
are  so  nearly  constant  that  they  cannot  of  themselves 
have  been  entirely  determined  by  the  choice  of  the  in- 
sect. Yet  this  may  not  preclude  the  possibility  of  the 
fact  that,  while  the  spots  were  produced  through  some 
other  agency,  certain  types  of  them  were  selected  by 
sexual  preference. 

If  attractive  coloration  Is  effective  anywhere  in  the 
animal  world,  it  will  possibly  be  found  among  the  in- 
sects, but  it  is  especially  likely  to  be  found  among  the 
birds.  Very  many  field  workers  in  these  groups  feel 
quite  sure  of  the  value  of  attractiveness.  When  but- 
terflies chase  each  other  up  and  down,  circling  and 
doubling,  following  each  other  for  long  distances,  it 
would  certainly  seem  as   if  they  were  pleased  with 


ADAPTATION    FOR    THE   SPECIES  1 29 

each  other's  appearance.  Some  naturahsts,  especially 
those  who  have  worked  chiefly  in  the  laboratory,  in- 
sist that  it  is  the  odor,  not  the  color  of  these  insects, 
which  is  attractive,  and  some  experiments  which  have 
been  made  would  seem  to  point  in  this  direction.  But 
the  creatures  experimented  upon  most  carefully  were 
night-flying  moths,  and  it  is  quite  possible  that  the 
sense  of  sight  in  the  night-flying  moths  has  lost  its 
vigor. 

The  great  difficulty  in  understanding  sexual  attrac- 
tion in  insects,  as  based  upon  beauty,  lies  in  the  un- 
doubtedly lower  development  of  their  nervous  activ- 
ity; in  other  words,  in  the  apparent  absence  of  any- 
thing w^orth  calling  mind.  I  think  no  one  imagines 
that  a  butterfly,  looking  upon  two  other  butterflies 
who  are  competing  for  her  affections,  deliberates  be- 
tween them  and  determines  to  admit  to  the  circle  of 
her  friendship  the  more  brilliantly  colored  male. 
Moths  are  so  irresistibly  attracted  to  a  light  as  to  fly 
into  it  without  apparent  power  to  withstand  its  influ- 
ence. They  repeat  the  flight  again  and  again  until 
they  are  destroyed.  If  they  react  so  vigorously  to 
the  stimulus  of  the  light,  it  seems  not  impossible  that 
they  may  also  act  vigorously  to  the  stimulus  of  color 
pattern,  and  that  the  male  most  beautifully  colored, 
according  to  the  nervous  ideal  of  the  female,  should 
win  her  unconscious  regard.     At  least  it  is  certain 


130  THE    MEANING    OF    EVOLUTION 

that,  in  very  many  of  the  butteiihes  and  moths,  the 
attractive  coloration  is  chiefly  displayed  when  they  are 
moving-  actively  about;  and  when  they  alight  and 
their  enemies  can  the  more  easily  capture  them,  they 
conceal  their  brilliant  colorings.  Most  butterflies  are 
very  brilliant  on  the  upper  surface  of  the  wings  and 
very  much  duller  on  the  under  surface.  Hence  in 
flight  they  show  their  colorings  exquisitely,  but  when 
they  alight,  and  are  thus  more  likely  to  be  captured, 
they  fold  the  brilliant  surfaces  together  in  an  upright 
position.  In  this  way  not  only  is  the  dull  side  of  the 
wings  placed  outward,  but  the  wings  themselves  are 
placed  edgewise  to  the  sky,  and  it  is  from  this  direc- 
tion that  their  enemies,  the  birds,  are  most  likely  to  see 
them.  Once  upon  the  wnng  these  creatures  display 
their  beauty  with  much  greater  safety  because  they 
can  escape  the  birds  very  readily  by  use  of  their  ex- 
ceedingly jerky  flight.  The  butterfly's  motion  is  as 
irregular  as  any  we  have  except  the  bat's.  This  ec- 
centricity is  one  great  element  in  their  safety,  and 
makes  it  less  dangerous  for  them  to  display  their  at- 
tractive colorations. 

One  very  large  group  of  the  night-flying  moths 
have  been  named  the  "underwings,"  because  of  the 
fact  that  their  hind  wings  are  very  much  more  bril- 
liant than  the  front,  and  in  lighting  they  fold  the  dull 
pair  back  over  the  bright,  completely  concealing  them. 


ADAPTATION    FOR    THE    SPECIES  I3I 

These  creatures  are  in  the  habit  of  resting  in  the  day- 
time against  walls,  or  stones,  or  the  bark  of  trees. 
The  similarity  in  color  between  their  front  wings, 
which  alone  show  while  sitting,  and  the  background 
on  which  they  rest,  is  most  remarkable.  One  may 
pass  them  again  and  again,  although  they  are  of  con- 
siderable size,  and  not  notice  them  at  all.  Once  let 
them  display  their  hind  wings  and  the  brilliancy  of 
their  color  always  attracts  immediate  attention. 

It  is  among  birds,  however,  that  brilliant  coloration 
serves  its  most  effective  purpose.  The  birds  are  alert, 
exceedingly  quick  of  sight,  and  are  much  more  dis- 
criminating than  insects  in  almost  every  respect.  It 
is  not  so  impossible  that  these  creatures  might  even 
voluntarily  prefer  a  distinctly  more  brilliant  mate, 
though  the  voluntary  character  of  the  process  is  not 
essential  to  its  success.  Men  certainly  are  constantly 
attracted  to  women  for  Avhose  charm  it  would  puzzle 
them  to  account.  If  this  is  true  with  regard  to  men, 
it  is  certainly  probable  that  birds  would  be  largely  in- 
fluenced by  phases  of  attractiveness,  of  which  they 
were  observant,  but  unconscious. 

Certain  it  is  that  in  many  birds  the  males  are  far 
more  beautiful  than  the  females.  Perhaps  the  com- 
monest illustration,  and,  at  the  same  time,  one  of  the 
best  is  found  in  the  so-called  red-wing  or  swamp 
blackbird.     The  male  of  this  creature  is  a  brilliant 


132  THE   MEANING   OF   EVOLUTION 

black,  excepting  that  upon  the  angle  of  the  wing, 
spoken  of  roughly  as  his  shoulder,  though  in  reality 
it  is  equivalent  to  our  wrist,  there  appears  a  splendid 
orange  patch  with  a  border  of  lemon  yellow.  When 
he  folds  his  wing  he  pushes  this  colored  angle  of  the 
wing  so  deftly  under  the  feathers  of  his  shoulder  as 
almost  to  conceal  it  When  in  flight  the  bird  is  ex- 
ceedingly conspicuous,  showing,  with  every  bend  and 
twist  of  his  body,  his  gorgeous  epaulets.  Meanwhile, 
the  female  is  likely  to  pass  unnoticed.  She  is  dull  in 
color  and  streaked  like  the  grass  among  which  she 
lives.  During  the  mating  season  the  male  hovers 
about  her,  swaying  from  side  to  side  in  such  a  way  as 
certainly  to  make  it  appear  as  if  he  realized  his  good 
points  and  was  bringing  them  to  bear  as  effectively 
as  he  knew  how.  After  his  mate  has  nested  and  is 
rearing  her  young,  it  would  appear  that  the  male  uses 
his  brilliancy  to  lure  the  observing  enemy  away  from 
the  nest  containing  his  wife  and  children. 

Another  illustration  of  the  remarkable  superiority 
of  the  male  over  the  female,  in  many  parts  of  the 
bird  world,  is  seen  in  the  case  of  the  common  barn- 
yard fowl.  The  rooster  is  so  much  more  gorgeous 
than  the  hen  that  anyone  reasonably  acquainted  with 
these  birds  cannot  have  failed  to  notice  the  fact.  In 
some  of  our  modern  varieties  we  have  by  breeding 
colored  them  nearly  alike.       The  original  chicken  is 


ADAPTATION    FOR    THE   SPECIES  1 33 

colored  much  like  the  common  Leghorns.  Shades  of 
red  and  yellow  decorate  his  neck  and  back,  while  the 
flight  feathers  of  his  wings  and  of  his  tail  and  the 
sickle  feathers  which  ornament  the  rear  of  his  back 
and  hang  over  his  tail  are  lustrous  dark  green.  The 
hen  meanwhile  is  very  much  less  brilliant  in  her  con- 
trasts. I  shall  speak  more  fully  of  this  in  discussing 
polygamy. 

The  attraction  of  beauty  is  not  the  only  lure  by 
which  a  creature  may  win  its  mate.  Sound  may  cap- 
tivate as  effectively  as  beauty.  This  is  true  of  insects 
as  well  as  of  birds.  Certain  insects  at  least  advise 
their  mates  of  their  presence  by  means  of  a  sound 
which  they  emit.  This  is  particularly  noticeable 
among  the  group  of  straight-winged  insects  to  which 
the  grasshopper,  katydid  and  cricket  belong.  The 
grasshopper  has  a  ridge  on  the  angle  of  his  wing  and 
a  roughness  on  the  side  of  his  leg.  When  these  two 
are  rubbed  together  the  result  is  sometimes  a  fiddling, 
sometimes  a  snapping  or  cracking  sound,  differing  in 
different  grasshoppers.  I  doubt  not  these  sounds  are 
pleasing  to  the  female  of  the  species,  for  they  are  al- 
ways made  by  the  male.  The  katydid,  instead  of  fid- 
dling in  this  way,  has  a  sort  of  drum  on  the  angle 
of  his  one  wing,  which  he  can  rub  over  a  tooth  in 
the  corresponding  angle  of  his  other  wing,  thus  pro- 
ducing the  familiar  "katydid"  sound.     I  have  never 


134  THE    MEANING    OF    EVOLUTION 

succeeded  in  making  a  dead  grasshopper  fiddle,  but  I 
have  long  known  how  to  make  a  dead  katydid  say 
"ka."  Quite  recently  I  have  added  to  my  accomplish- 
ment in  this  respect  and  can  make  it  say  "katy."  The 
"did"  part  of  the  song  still  lies  beyond  my  power. 
The  crickets  produce  their  sharp  notes  in  much  the 
same  fashion  as  the  katydids. 

One  observer  of  the  chirping  of  the  cricket  says 
that  the  pitch  of  the  song  varies  with  the  tempera- 
ture. He  has  even  worked  out  a  formula  by  which 
one  can  tell  the  pitch  of  the  chirp,  if  he  knows  the 
temperature,  or,  knowing  the  temperature,  can  de- 
termine the  pitch.  Of  course  this  is  too  mechanical; 
yet  it  indicates  that  there  must  be  considerable  rela- 
tion between  the  two ;  the  warmer  the  cricket  the  hap- 
pier he  is. 

It  is  the  males  among  insects  that  chirp  their  love 
songs.  The  females  never  answer  them.  There  is  a 
peculiar  notion  that  the  female  katydid,  w^hen  thus  ac- 
cused of  some  offense,  replies  "katy  didn't."  The 
truth  of  the  matter  is  that  no  female  katydid  ever  re- 
plied to  the  accusations  of  her  lover,  if  accusation  it 
be.  She  is  absolutely  dumb,  not  having  the  drum 
upon  her  wings  with  wdiich  to  reply.  She  is  provided 
w^ith  cars  w^herewnth  to  hear,  and,  strange  to  say,  she 
keeps  them  on  her  elbow,  as  does  also  the  cricket, 


ADAPTATION    FOR    THE    SPECIES  1 35 

while  the  grasshopper  has  his  ears  upon  the  side  of 
his  body. 

Everyone  who  lives  in  the  country,  or  goes  into  the 
country  in  the  summertime,  is  sure  to  know  the  hum- 
ming of  the  so-called  locust.  It  is  an  unfortunate  fact 
that  the  word  locust  may  have  several  meanings.  It 
is  properly  applied  to  one  group  of  the  grasshoppers. 
The  creature  most  commonly  called  a  locust  is  a 
cicada,  or  harvest  fly.  When  the  weather  gets  quite 
warm  the  cicada  starts  his  love  song.  He  has  two 
long  flaps  to  his  vest,  and  under  each  flap  he  has  a 
vibrating  drum  head.  This  is  set  shivering  by  a  mus- 
cle on  its  under  side.  The  female  cicada  again  is 
silent. 

It  is  among  birds  that  the  love  song  reaches  its 
finest  development.  It  may  consist  simply  of  a  little 
chirp  as  in  the  chippy.  It  may  consist  of  two  notes 
of  a  different  pitch  repeated  steadily,  as  in  the  tufted 
titmouse.  It  may  attain  considerable  variation,  as  in 
the  robin.  But  in  the  choir  of  our  best  singers,  like 
the  catbird,  thrasher,  and  mocking  bird,  there  is  un- 
ending variation  of  notes.  It  seems  almost  impossible 
to  doubt  the  charming  quality  of  this  voice  upon  the 
mate.  It  certainly  is  chiefly  confined  to  the  mating 
season,  and  is  indulged  in  almost  entirely  by  the 
males.  This  does  not  mean  that  a  male  does  not  sing 
excepting  when  he  wishes  to  charm  his  mate.     But 


136  THE    MEANING    OF    EVOLUTION 

the  time  when  he  is  in  his  most  exquisite  feather  and 
most  charming  mood  is  the  time  when  he  sings  most 
sweetly,  and  this  is  the  time  when  he  is  taking  to  him- 
self a  mate.  The  love  joy  may  so  overcrowd  his  life 
that  he  sings  much  and  often,  but  the  increase  in  its 
amount  and  character  during  the  mating  season  seems 
to  proclaim  its  purpose  beyond  a  doubt. 

In  addition  to  the  allurements  above  described  there 
are  certain  peculiar  behaviors  of  the  animal  during  the 
mating  season  which  are  intensely  interesting.  Some- 
times they  consist  simply  of  a  wild  delirium  of  joy, 
which  overpowers  the  animal  completely  and  makes 
him  do  wonderful  things.  Birds  will  fly  with  impetu- 
ous leaps  in  the  air,  mount  higher  and  higher,  singing 
wildly,  only  to  turn  suddenly  at  the  top  of  the  flight 
and  drop  promptly  to  the  ground.  I  have  seen  such 
ecstatic  flights  in  the  oven  bird  and  in  our  rollicking 
gold  finch.  I  have  seen  a  catbird  on  his  way  to  a  tree 
turn  three  somersaults,  much  like  those  performed  by 
a  tumbler  pigeon,  after  which  he  alighted  upon  the 
bough.  None  of  these  acts  seemed  deliberately  per- 
formed in  front  of  the  females,  but  I  have  seen  three 
or  four  killdeer  parading  in  most  stately  and  precise 
manner,  spreading  their  wnngs  and  fluffing  their 
feathers,  performing  a  sublimated  cup-and-cake  walk 
amid  a  circle  of  attracted  females. 

Even  our  little  English  sparrow,  as  I  have  previ- 


ADAPTATION    FOR    THE   SPECIES  1 37 

ously  mentioned,  fluffs  himself  up  and  spreads  his 
wings  and  prances  around  in  front  of  his  presumably 
adoring  ladylove.  But  the  weirdest  performance  of 
this  sort  I  have  ever  seen  is  that  shown  by  the  male 
ostrich.  When  he  becomes  excited,  swaying  his  body 
from  side  to  side,  he  sinks  slowly  upon  his  knees,  until 
his  body  touches  the  ground,  his  wings  spread  on 
either  side  and  the  feathers  fluffed  up  so  as  to  show 
every  exquisite  plume  in  all  its  splendid  beauty.  The 
long  neck  is  laid  back  until  the  head,  which  is  doubled 
sharply  forward,  is  pressed  almost  against  the  back, 
and  in  this  strange  position  he  sways  from  side  to 
side,  apparently  utterly  oblivious,  for  a  time,  of  every- 
thing. After  about  a  minute  of  this  performance,  he 
seems  slowly  to  come  to  himself  and  rise  again  to  his 
feet.  Now  he  is  particularly  likely  to  make  vicious 
attack  upon  anything  within  reach. 

It  is  not  only  necessary  that  the  animal  should  be 
able  to  attract  a  mate.  There  may  be  more  than  one 
claimant  for  the  damsel's  affection.  In  many  animals 
we  see  provisions  whereby  the  male  may  effectively 
deal  with  his  rivals.  This  is  especially  likely  to  be 
the  case  if  the  animal  be  a  polygamist.  In  every  spe- 
cies there  are  produced  about  as  many  males  as  fe- 
males. If  the  polygamous  habit  leads  one  male  to 
gather  about  him  a  group  of  females,  with  whom  he 
mates,  it  is  evident  that  he  is  displacing  an  equal  num- 


138  THE    MEANING    OF    EVOLUTION 

ber  of  rivals,  and  they  are  not  willingly  displaced. 
Accordingly  we  find  that  polygamy  is  usually  accom- 
panied by  a  belligerent  disposition  on  the  part  of  the 
males.  In  our  ordinary  barnyard  fowl  this  trait  is 
very  evident.  The  rooster  not  only  domineers  over 
the  hens,  not  only  struts  about  among  them  in  stately 
fashion  and  gives  vent  to  his  feelings  by  his  sonorous 
voice,  he  must  also  drive  away  from  the  neighborhood 
any  rivals  for  the  affections  of  his  wives.  Hence  the 
rooster  attacks  upon  sight  the  neighboring  rooster, 
and  battles  with  him  to  his  entire  discomfiture  and 
sometimes  to  the  death. 

Among  the  members  of  the  deer  family  this  partic- 
ular phase  of  the  relation  between  the  sexes  has  pro- 
duced in  the  males,  and  only  very  rarely  in  the  fe- 
males, the  magnificent  branching  horns.  These  are 
intended  not  so  much  as  a  protection  against  the 
enemy  as  for  an  offensive  w^eapon  in  the  battle  for  the 

mates. 

Beautiful  and  stately  as  are  these  magnificent  horns, 
they  last  only  for  a  part  of  the  year.  We  begin  to 
understand  their  meaning.  When  the  w^olf  is  hungri- 
est, toward  the  close  of  the  bitter  winter,  the  deer  is 
without  horns.  When  the  time  for  mating  comes,  the 
deer  within  a  few  weeks  grows  his  horns,  which  at  ^ 
first  are  covered  with  a  plushlike  coating,  known  as 
velvet.     After  a  while  this  dries  and  he  rubs  his  horns 

t 


ADAPTATION    FOR    THE    SPECIES 


139 


against  the  trees  until  they  are  clean  and  smooth. 
Now  he  is  ready  for  the  battle  royal. 

In  the  case  of  the  fur  seals  polygamy  has  carried  its 
specialization  of  the  males  to  a  remarkable  extent. 
The  bull  seals  are  several  times  as  large  as  the  cows, 
and  are  provided  with  terrific  canine  teeth.  With 
these  they  battle  with  a  violence  that  very  often  re- 
sults in  the  death  of  one  of  the  combatants.  A  suc- 
cessful bull  seal  who  has  gathered  about  him  a  clus- 
ter of  seal  cows  is  seamed  and  scarred  with  the  marks 
of  his  annual  combats. 

One  more  type  of  adaptation  can  be  profitably  con- 
sidered. Animals  have  developed  many  devices  which 
serve  for  the  protection  of  their  young.  The  wonder- 
ful silk  spun  by  the  spider  was  evidently  primarily  in- 
tended to  serve  as  a  covering  for  the  eggs.  Probably 
all  of  our  spiders  agree  in  using  the  silk  for  this  pur- 
pose. Many  of  them  employ  it  for  practically  no 
other,  though  there  are  half  a  dozen  different  uses 
to  which  different  spiders  may  put  their  silk.  Under 
these  conditions  we  have  a  right  to  infer  that  silk  was 
primarily  developed  as  a  coating  for  the  eggs.  In 
the  case  of  some  of  our  spiders  a  little  fluffy  mass  of 
silk  covers  the  egg,  while  a  firmly  woven  sheet  of  silk 
covers  both  egg  mass  and  fluff,  holding  it  flat  against 
a  wall  or  the  trunk  of  a  tree.  In  some  of  the  higher 
spiders,  notably  our  bank  spiders,  the  silken  covering 


I40  THE    MEANING    OF    EVOLUTION 

becomes  an  effective  cocoon,  spherical  in  shape,  with  a 
Httle  opening  at  the  top  Hke  the  neck  of  a  small  bottle. 
The  egg  cocoon  is  woven  in  a  mass  of  tangled  silk 
between  the  branches  of  some  tough  weed  which  will 
be  sure  to  outlast  the  winter.  Into  the  egg  cocoon  the 
spider  may  place  one  thousand  or  more  eggs.  Having 
thus  provided  her  children  with  a  snug  winter  home, 
the  spider  dies.  When  spring  comes  with  the  warm 
rays  of  the  sun,  the  eggs  hatch  and  the  cocoon  be- 
comes a  creeping  mass  of  minute  spiders.  At  the 
time  these  spiders  appear  there  is  nothing  for  them 
to  eat.  The  obvious  way  out  of  this  difficulty  is  taken. 
At  once  there  begins  a  progressive  party.  Spider 
fights  with  spider,  and  the  prize  in  each  conflict  is  the 
body  of  the  victim,  which  is  promptly  eaten.  The 
winners  in  the  first  round  pair  off  again,  and  a  little 
later,  as  hunger  drives  them,  another  set  of  combats 
comes  on,  resulting  in  another  halving  of  the  number 
of  spiders  in  the  cocoon.  This  process  continues  un- 
til not  more  than  one-tenth  of  the  original  number  of 
spiders  remains.  By  this  time  they  have  gained  suffi- 
cient strength  of  leg  and  jaw,  and  sufficient  dexterity 
in  the  use  of  both,  to  make  it  safe  for  them  to  ven- 
ture out  and  try  their  fortunes  among  the  accidents 
of  a  strenuous  world.  There  can  be  little  doubt  after 
this  long  process  has  w^orked  its  final  results  which 
tenth  remains.     Chance  plays  but  small  part  in  this 


ADAPTATION    FOR    THE    SPECIES  I4I 

game.  It  is  the  fittest  that  survive.  When  this  pro- 
cedure goes  on  generation  after  generation,  the  result 
must  necessarily  be  that  the  spiders  grow  fitter  and 
fitter  for  their  work.  This  method  is  hard  on  the 
little  spider,  but  it  makes  good  spiders. 

Most  insects  die  before  their  eggs  hatch;  accord- 
ingly they  can  pay  no  attention  to  their  own  children. 
Whatever  arrangements  are  provided  for  the  safety 
and  strength  of  these  offspring  must  be  provided  be- 
fore they  appear.  About  the  only  care  the  majority 
of  insects  take  in  this  direction  is  to  see  that  the  eggs 
are  placed  where  the  young  shall  find  food  as  soon 
as  they  emerge.  Insects'  eggs  are  very  small,  and  as 
a  consequence  the  creatures  which  emerge  from  them 
are  likewise  exceedingly  minute.  As  a  result  they 
cannot  be  expected  to  hunt  far  for  their  food.  Differ- 
ent insects  use  different  devices  by  which  to  overcome 
this  difficulty.  The  katydid,  for  Instance,  must  die 
with  the  approach  of  fall.  Her  children  will  not  ap- 
pear until  the  following  year.  Her  food  consists  of 
leaves,  but  to  lay  the  eggs  in  such  a  situation  would 
be  a  fatal  process,  because  the  leaf  will  drop  off 
before  the  eggs  hatch.  Accordingly,  the  katydid  lays 
its  shield-shaped  eggs  in  a  double  row  near  the  end  of 
a  young  twig.  Next  year  when  the  weather  is  suffi- 
ciently warm  to  hatch  katydids,  it  is  also  warm 
enough  to  force  the  buds  on  the  end  of  the  twigs. 


142  THE    MEANING    OF    EVOLUTION 

When  the  katydids  arrive  their  jaws  are  young  and 
tender,  but  so  are  the  leaves  upon  which  they  are  born. 
Hence  there  is  httle  difiiculty  on  the  part  of  the  young 
katydids  in  finding  an  abundance  of  food.  By  the 
time  the  leaves  have  grown  tougher,  the  katydid's 
jaws  are  stronger,  and  the  leaves  will  still  serve  as 
food. 

Everyone  who  is  at  all  familiar  with  country  life 
and  gardening  is  familiar  with  what  is  called  the  po- 
tato or  tomato  worm.  It  is  a  long,  green,  smooth, 
caterpillar,  as  long  and  as  fat  as  your  linger  and  pro- 
vided with  a  horn  upon  his  tail.  The  gardener  may 
not  know  that  after  a  while  this  creature  will  burrow 
into  the  ground,  and  there  change  into  an  oblong 
brown  mass  with  a  sort  of  a  pitcher  handle  at  one 
side.  Next  year  this  pupa  will  split  down  the  back, 
and  from  out  of  the  brown  case  will  come  a  hawk- 
moth,  which  soon  will  fly  with  rapidly  quivering  wings 
and  feast  upon  the  nectar  of  our  moon  flowers  or  on 
that  of  the  "Jimson"  weed.  Those  who  have  cleaned 
these  pests  from  the  potato  or  tomato  vines  will  often 
have  noticed  one  of  them  covered  with  wdiat  look  al- 
most like  grains  of  rice.  This  appearance  reveals  an 
interesting  story.  Some  time  earlier  an  insect  that 
looked  very  much  like  a  dainty  wasp  with  a  rather 
long  sting  in  its  tail  hovered  over  the  caterpillar.  This  f 
is  the  ichneumon  fly.     Eventually  lighting  upon  the         a 


ADAPTATION    FOR    THE    SPECIES  I43 

caterpillar's  back,  it  punctured  the  skin  with  its  sting, 
and  deposited  eggs  within  the  caterpillar's  body. 
These  eggs  soon  hatched  and  the  little  grubs  worked 
their  way  through  the  body  of  its  host.  The  infested 
victim  feeds  upon  leaves  and  fills  itself  with  rich  food. 
These  parasites  eat  the  food,  and,  try  as  it  may,  the 
caterpillar  does  not  succeed  in  getting  fat.  After  the 
grubs  have  gotten  their  full  growth,  each  of  them  eats 
its  way  through  a  little  hole  to  the  outside  of  the 
caterpillar's  body.  Here  it  spins  around  itself  a  little 
white  case,  and  looks  like  a  rice  grain.  As  the  cater- 
pillar moves  about,  these  seeming  rice  grains  are 
rubbed  off  and  fall  to  the  ground.  Next  year  there 
will  come  up  new  ichneumon  flies  to  sting  fresh  cater- 
pillars and  repeat  the  entire  process. 

Another  remarkable  provision  for  the  young  on  the 
part  of  insects  is  seen  in  the  behavior  of  the  big 
sphex  wasp,  known  as  the  cicada  killer.  The  cicada, 
it  will  be  remembered,  is  what  is  commonly  called  a 
locust.  The  cicada  killer  is  a  magnificent  big  wasp, 
whose  body  is  nearly  an  inch  long,  banded  with  black 
and  yellow,  while  the  wings  are  colored  a  smoky 
brown.  This  muscular  wasp  digs  a  long  tunnel  eight 
or  ten  inches  deep,  which  ends  in  a  slightly  larger 
room.  Having  provided  the  location,  he  now  sallies 
forth  in  search  of  the  cicada.  The  heavy  song  of  the 
male  probably  serves  as  a  guide  to  the  wasp  in  case 


f 


I 


144  THE    MEANING   OF   EVOLUTION 

of  scarcity  of  cicadas,  but  the  killer  has  apparently 
little  difficulty  in  finding  his  prey.  The  wasp  pounces 
upon  the  insect,  and  in  spite  of  its  strength  and  the 
thrashing  of  its  vigorous  wings  punctures  it  with  his 
sting  again  and  again.  The  poison  of  the  sting  enter- 
ing into  the  nerve  centers  gradually  paralyzes,  but 
usually  does  not  kill,  the  cicada.  Now  the  killer  car- 
ries its  prey  home,  pushes  it  to  the  bottom  of  the  tun-  f 
nel  and  deposits  upon  it  a  single  egg.  The  wasp 
closes  up  the  hole  and  leaves  the  place.  When  the  egg 
hatches  and  the  grub  of  the  wasp  emerges,  it  finds  a 
big  cicada  just  at  hand,  upon  which  it  feeds.  By  the 
time  the  cicada  is  completely  devoured,  the  wasp  grub 
has  obtained  its  full  growth.  After  a  short  period  of 
development  a  new  sphex  wasp  is  ready  to  work  its 
way  out  of  the  tunnel,  find  a  mate,  dig  a  hole,  and 
safely  provide  for  its  own  children. 

Still  more  remarkable  adaptations  for  the  care  of 
the  young  appear  among  the  birds.  Here  the  eggs  are 
not  to  be  deserted,  but  are  to  be  cared  for  until  the 
young  appear.  These  again  must  have  attention  until 
such  time  as  they  are  quite  able  to  take  care  of  them- 
selves. The  birds  are  warm-blooded  animals,  and 
even  their  young,  while  they  are  developing  in  the 
egg,  are  warm-blooded.  Consequently  the  tempera- 
ture of  the  egg  must  be  maintained  evenly  and  uni- 
formly, or  there  will  be  no  development. 


f 


ADAPTATION    FOR    THE   SPECIES  I45 

The  fish  may  drop  its  eggs  carelessly  upon  the  bot- 
tom of  the  stream.  A  frog  may  deposit  them  in  a 
mass  of  jelly  and  leave  them  forever.  A  turtle  may 
bury  its  eggs  in  a  sand  bank  and  abandon  them  to 
their  fate.  The  warm  blood  of  the  young  bird  de- 
mands more  attention  than  this.  Accordingly,  the 
parent  bird  has  learned  to  make  for  itself  some  sort 
of  nest,  in  which  the  young  may  be  kept  properly 
warm  until  they  are  developed.  The  ancestral  bird, 
who  was  to  be  the  progenitor  of  the  entire  bird  class, 
must  have  had  somiC  very  simple  method  of  providing 
a  place  in  which  its  eggs  might  be  hatched.  As  the 
descendants  of  this  original  bird  have  passed  into  new 
situations,  the  various  lines  have  taken  upon  them- 
selves different  shapes  until  we  have  the  multiform 
birds  of  to-day.  The  habits  of  the  birds  have  also 
varied.  Each  has  adapted  itself  to  the  situation  in 
which  it  found  itself,  and  no  adaptation  has  been 
more  varied  and  effective  than  the  adjustment  of  the 
nesting  site.  Nests  are  found  upon  the  ground,  in 
the  bushes,  on  the  lower  limbs,  in  the  crotches  of  the 
trees,  in  the  trunks  of  the  trees,  upon  their  very  sum- 
mits, and  on  the  tops  of  inaccessible  crags.  To  every 
sort  of  situation  some  bird  has  been  enabled  to  adapt 
itself.  This  has  made  it  possible  for  very  many  more 
birds  to  thrive  than  could  have  found  a  place  in  the 
world,  had  they  all  lived  upon  the  same  plan. 


146  THE    MEANING    OF    EVOLUTION 

In  the  case  of  the  l)rir.k  swallow  his  nest  may  be 
a  very  simple  contrivance,  consisting  only  of  a  tunnel 
running  back  into  a  bank,  and  widening  at  the  back. 
Some  material  that  will  soften  the  bed  upon  which 
eggs  are  to  be  laid  must  be  placed  in  this  cavity.  The 
whole  home  is  a  very  simple  and  crude  affair.  But 
little  better  is  the  arrangement  which  the  woodpecker 
calls  a  home.  This  has  been  cut  into  the  dry  wood  of 
a  defective  tree.  No  woodpecker  can  make  his  home 
in  absolutely  solid  sapwood.  Hence  the  first  labor  of 
the  woodpecker  must  consist  in  finding  a  place  in 
which  it  can  dig.  If  there  is  an  old  stump  of  a  limb 
sticking  up,  the  problem  is  readily  solved.  Such 
wood  has  no  sap  in  it,  and  is  brittle  enough  to  be  eas- 
ily dug  out.  But,  if  there  be  no  such  stub,  the  wood- 
pecker will  find  a  suitable  place  in  most  trees.  At 
some  time  or  other  almost  every  tree  loses  a  big  limb. 
When  such  accident  occurs  there  will  always  be  in  the 
old  trunk  a  region  through  which  sap  once  went  to 
this  limb.  This  region,  deprived  of  its  function,  goes 
completely  dry,  like  the  heartwood  of  the  tree,  and  it 
is  into  such  material  as  this  that  the  woodpecker  suc- 
ceeds in  drilling  his  well-protected  home. 

As  birds  rise  higher  in  the  scale  the  nest-building 
becomes  a  more  complicated  affair,  and  after  a  while 
we  find  a  well-woven  substantial  nest,  through  which 
even  the  air  will  not  chill  the  eggs  enough  to  prevent 


ADAPTATION    FOR    THE   SPECIES  I47 

their  hatching,  while  the  warmth  is  snpph'ed  by  the 
mother's  body.     It  is  often  a  matter  of  surprise  to 
many  people  that  a  bird  should  contrive  to  build  a  nest 
so  exquisitely  circular.     The  trick,  after  all,   is  not 
quite  so  difficult  as  it  looks.     The  robin  gathers  up  a 
few  sticks  and  places  them  as  the  beginning  of  the 
platform.     More  and  more  are  brought  and  woven 
into  each  other,  making  a  framework  altogether  too 
big  for  the  nest.     Then  mud  is  brought  and  plastered 
inside  of  this.     With  the  plastering  of  this  mud  the 
careful  circularity  of  the  work  begins.     Every  time  a 
little  material  has  been  added  the  robin  sits  down  in 
the  nest  and  revolves  her  body,  in  this  way  shaping 
the  interior  much  as  the  potter  shapes  a  pot.     In  the 
case  of  the  artisan,  it  is  the  pot  that  revolves.     In  the 
case  of  the  robin,  the  bird  itself  revolves.    The  efifect 
is  the  same  in  both  cases — a  circular  vessel  is  pro- 
duced.   A  little  lining  added  to  the  interior  of  the  nest 
softens  it  for  the  reception  of  the  eggs.     In  this  ex- 
quisite home  the  robin  lays  her  eggs,  and  sits  upon 
them  until  they  are  developed  enough  to  hatch,  and 
then  feeds  the  young  until  they  are  old  enough  to 
feed  themselves. 

Far  more  remarkable  than  any  of  the  devices  thus 
far  described  are  the  wonderful  developments  which 
have  come  in  the  class  of  animals  known  as  the  mam- 
mals.    Here  the  most  wonderful  protection  is  made 


148  THE    MEANING   OF    EVOLUTION 

for  the  care  and  feeding  of  the  young.     But  this  is  to 
be  the  subject  of  a  separate  chapter. 

As  long  as  we  thought  of  each  sort  of  animal  as  be- 
ing a  separate  species  shaped  in  the  beginning  by  the 
hands  of  the  Creator,  each  of  these  devices  seemed  to 
us  a  new  manifestation  of  the  Divine  Providence, 
whose  fertile  planning  had  conceived  so  many  methods 
of  providing  for  his  children.  Unconsciously  we 
thought  of  God  acting  as  man  acted.  Each  animal 
seemed  a  purely  separate  invention  purposely  designed 
for  an  especial  place.  Now  we  understand  the  plan 
in  creation  better,  and  see  that  each  animal  has  come 
from  another  not  quite  like  itself,  some  distance 
back,  and  this  from  still  another.  Our  admiration 
for  these  devices  as  they  arise  through  evolution  is 
no  less,  but  takes  on  another  form. 


CHAPTER  VI 

Life  in  the  Past 

Anyone  who  earnestly  studies  plants  and  animals 
as  they  exist  in  the  world  to-day  cannot  help  wonder- 
ing how  the  earth  began  and  where  it  got  its  life. 
This  is  the  true  end  and  aim  of  geological  study.  The 
history  of  man  seems  to  run  back  into  a  far  distant 
and  gloomy  past.  Except  for  the  poetical  account  in 
Genesis  and  the  traditions  of  various  peoples  through- 
out the  world,  real  history  fades  away  into  an  earlier 
time  of  which  there  are  no  written  records.  When 
the  delvers  in  the  Mesopotamian  plain  talk  to  us  of 
kingdoms  running  back  through  seven  or  eight  or 
nine  thousand  years,  we  seem  to  be  getting  back  to 
the  beginnings  of  things.  But  seven  or  eight  or  nine 
thousand  years  are  as  nothing  in  comparison  with  the 
age  of  the  earth,  which  runs  back  into  a  past  so  lim- 
itless that  no  man  can  safely  assign  any  set  figure  to 
it.  In  a  recent  paper,  Dr.  Walcott,  of  the  Smith- 
sonian Institution,  says  that  the  antiquity  of  the  earth 
must  be  measured  not  in  millions,  for  they  are  too 
short,  nor  hundreds  of  millions,  for  this  carries  us  too 

149 


150  THE    MEANING    OF    EVOLUTION 

far,  but  must  surely  be  measured  in  tens  of  millions 
of  years. 

A\'hen  we  attempt  to  study  the  past  we  find  its  vari- 
ous epochs  unequally  clear  to  us.  In  human  history 
only  quite  modern  times  are  absolutely  clear.  The 
history  of  the  Middle  Ages  is  distinct  enough  for  us 
to  build  for  ourselves  a  picture  of  the  time  with  rea- 
sonable hope  of  gaining  a  correct  view  of  the  state  of 
affairs.  Back  of  this  comes  the  long  stretch  of  the 
Dark  Ages,  in  which  here  and  there  we  have  bright 
spots,  but  it  will  perhaps  long  be  impossible  to  portray 
clearly  the  life  of  the  people.  Getting  back  to  the 
Romans,  things  once  more  become  reasonably  plain, 
as  is  true  also  in  the  case  of  Greek  history.  Back  of 
this  stretches  the  Egyptian  with  fair  precision,  and, 
older  than  it,  the  Babylonian  and  Chaldean.  But  these 
past  three  have  not  left  nearly  so  definite  an  account 
for  us  as  did  the  later  civilizations  of  Greece  and 
Rome. 

When  we  try  to  go  back  of  these  we  must  change 
our  method  of  study  entirely.  Writing  is  absent,  and 
all  we  know  of  earlier  men  must  be  inferred  from  a 
few  pictures  that  were  daubed  on  the  rocks  or  carved 
in  ivory  or  bone,  from  tools  made  of  stone  or  bone, 
from  a  few  metal  or  stone  ornaments,  or  from  the 
bones  of  the  men  themselves.  Even  so,  the  history 
fades  out  without  tellinc:  us  its  own  beciinninsis.     It 


LIFE   IN    THE    PAST  I5I 

is  quite  as  impossible  for  history  to  write  its  origins 
as  it  is  for  man,  from  his  own  knowledge,  to  descrilje 
his  birth. 

What  is  true  of  the  human  story  is  quite  as  true  of 
that  of  the  earth.  Recent  steps  are  very  plain.  We 
may  read  them  with  considerable  confidence.  As  we 
go  deeper  into  the  rocks  and  find  older  fossils,  the 
evidence  becomes  less  certain.  The  animals  differed 
enough  from  those  of  to-day  for  us  to  be  less  sure 
what  they  were  like.  As  we  keep  on  moving  back- 
ward through  time,  and  downward  through  the  rocks, 
we  find,  after  a  while,  strata  in  which  there  are  evi- 
dences of  life  that  existed  long  ago,  but  in  which 
these  traces  are  so  altered  that  it  is  impossible  to  tell 
what  sort  of  living  things  existed ;  we  learn  only  that 
they  were  alive.  Going  back  still  further,  these  fade 
out.  There  is  no  knowing  when  the  earth  began; 
there  is  no  knowing  when  life  began  upon  the  earth. 
It  is  not  meant  that  men  have  not  wondered,  even 
reckoned  carefully,  as  to  how  long  ago  each  of  these 
events  occurred.  Many  speculations  have  proved  en- 
tirely useless,  a  few  remain  as  yet  neither  confirmed 
nor  disproved,  and  of  such  we  shall  speak. 

For  the  last  hundred  years  the  theory  of  the  earth's 
origin  suggested  by  the  Marquis  Pierre  Simon  De  La 
Place,  of  France,  near  the  end  of  the  eighteenth  cen-  V 
tury,   has  held  almost  undisputed   sway  among  men 


152  THE    MEANING    OF    EVOLUTION 

who  were  willing  to  consider  the  question  as  open  to 
human  solution.  This  theory  is  known  as  La  Place's 
Nebular  Hypothesis.  When  men  began  to  study  the 
heavenly  bodies  with  the  newly  invented  telescope, 
new  ideas  naturally  sprang  up.  Among  the  objects 
which  the  glass  disclosed  were  the  nebulcT,  which  are 
great  clouds  of  fire  mist,  glowing  masses  of  gas.  They 
are  scarcely  visible  to  the  naked  eye,  but  are  among 
the  most  interesting  objects  in  the  heavens  when  seen 
through  a  telescope.  The  other  suggestive  heavenly 
body  was  our  sister  planet,  Saturn.  Besides  having 
a  full  complement  of  moons,  Saturn  has  around  it,  as 
distant  as  we  would  expect  moons  to  be,  three  great 
rings.  These  look  very  much  as  if  one's  hat,  with 
an  enormously  wide  brim,  should  have  the  connection 
between  the  rim  and  the  hat  broken  out  completely, 
but  the  rim  should  still  float  around  the  hat  without 
touching  it  and  should  steadily  revolve  as  it  stood 
there.  The  rings  of  Saturn  are  not  solid  like  the  sug- 
gested hat  rim.  They  are  evidently  made  up  of  a 
great  number  of  very  small  particles,  each  moving 
around  the  center  of  Saturn.  But  the  great  cloud  of 
them  is  spread  out  flat.  At  the  distance  which  Saturn 
is  from  the  earth  they  look  as  if  they  made  a  solid 
sheet.  Furthermore,  they  do  not  form,  as  it  were, 
one  continuous  hat  rim,  but  it  is  as  if  the  rim  were 
broken  into  three  circular  sections,  each  bigger  than 


LIFE   IN    THE    PAST  1 53 

the  one  inside  it  and  separated  from  the  next  by  an 
area  nearly  as  wide  as  the  ring  itself. 

With  such  material  in  the  heavens  to  guide  him,  La 
Place  suggested  that  the  sun  had  once  been  an  enor- 
mous fire  mist  scattered  over  an  area  billions  of  miles  ^ 
in  diameter.  This  gaseous  material,  by  the  attraction 
of  its  particles  for  each  other,  began  to  condense  and 
contract.  When  the  plug  is  pulled  from  a  washbasin 
the  particles  of  water,  in  moving  toward  the  center, 
in  order  to  get  out  of  the  basin,  invariably  set  up  a 
rotary  motion.  As  the  particles  of  this  diffused 
nebula  began  to  gather  together  they,  too,  gave  to  the 
mass  a  rotary  movement.  This  grew  more  and  more 
rapid,  with  greater  contraction,  until  the  particles  on 
the  outer  edge  of  the  rotating  mass  had  just  so  much 
speed  that  the  least  bit  more  would  make  them  tend 
to  fly  off  as  mud  would  fly  from  a  revolving  wheel. 
When  this  point  was  reached  there  was  a  balance  of 
forces  which  made  the  outermost  portion  remain  as 
a  ring  while  the  rest  contracted  away  from  it,  leaving 
it  behind. 

It  was  La  Place's  idea  that  this  process  had  re- 
peated itself,  and  ring  after  ring  had  been  left  behind. 
Finally  the  sun  condensed  and  grew  into  a  ball,  oc- 
cupying the  center  of  the  system.  At  varying  dis- 
tances from  it  were  to  be  found  either  rings  or  planets 
which  had  been  formed  out  of  such  rings.     For  La 


154  THE    MEANING    OF    EVOLUTION 

Place  suggested  that  in  a  ring  like  this  the  material 
could  not  be  quite  evenly  distributed.  While  every 
particle  in  the  ring  kept  revolving  around  the  sun, 
those  in  front  of  the  densest  part  were  slowly  held 
back  by  the  attraction  of  the  thicker  portion,  while 
those  behind  it  in  rotation  had  their  speed  hastened 
until  finally  all  the  material  in  the  ring  had  collected 
at  one  spot  and  a  new  planet  was  born.  La  Place 
believed  that  these  planets  formed  their  moons  in  ex- 
actly the  same  way,  and  that  Saturn  was  simply  a 
planet  not  all  of  whose  moons  had  yet  been  formed. 
He  believed  that  this  happy  accident  served  to  tell  us 
how  the  universe  had  been  created. 

Of  course,  so  detailed  a  theory  concerning  anything 
of  which  we  know  so  little  has  always  had  much 
ridicule  thrown  upon  it,  and  yet  no  truly  competing 
theory  has  been  proposed  until  very  recent  times. 

Within  a  few  years  a  Planetesimal  Theory  has  been 
announced,  and  is  gaining  considerable  prominence, 
although  it  is  too  early  yet  to  say  whether  it  will 
supersede  La  Place's  idea.  In  this  theory,  also,  the 
suggestion  comes  from  the  heavenly  bodies.  With 
the  increasing  study  of  the  nebulas,  many  forms  of 
these  interesting  bodies  have  been  discovered.  A  very 
common  type  consists  of  a  great  coherent  central  mass, 
with  two  or  more  arms  extending  from  opposite  sides 
in  the  form  of  a  spiral.     This  is  as  if  gaseous  re- 

PROPERTY  OP 


V  ft  M.  CnLLEGE  LIBRARY^ 


LIFE  IN   THE   PAST  1 55 

volving  nebulae  had  come  into  comparatively  close 
proximity  to  a  passing  body.  The  visitor,  by  its  at- 
traction, drew  from  the  nebula  a  wisp  of  gas.  The 
revolving  motion  of  the  nebula  gave  to  the  attracted 
arm  the  spiral  form. 

These  twisted  arms  are  not  equally  dense  through- 
out, but  have  thickened  knots  here  and  there  in  their 
course.  The  Planetesimal  Theory  suggests  that  these 
thickened  knots  are  embryo  planets  and  the  central 
portion  of  the  nebulae  an  embryo  sun.  After  all  the 
material  in  such  a  body  has  condensed  either  around 
the  knots  or  about  the  central  mass  a  new  solar  sys- 
tem will  be  complete.  As  before  stated,  neither  of 
these  theories  can  be  said  to  be  demonstrated.  Each 
of  them  has  points  in  its  favor  and  each  has  its  diffi- 
culties. It  is  pleasant  to  know  what  men  have  clearly 
thought  concerning  such  questions,  but  for  a  man  not 
a  trained  geologist  neither  will  carry  much  convic- 
tion. He  will  still  rest  with  his  own  early  conclusion 
that  whichever  shall  prove  to  be  true,  for  him  his 
old  formula  is  still  valid,  "in  the  beginning  God  made 
the  heavens  and  the  earth."  He  will  no  longer  think 
of  God  as  having  shaped  the  balls  with  his  own  hand 
and  thrown  them  into  space ;  he  will  no  longer  dream 
that  it  all  occurred  within  a  week  not  more  than  six 
thousand  years  ago;  but  still  to  him  will  come  the 
reverent  conviction  that,  whatever  the  plan  by  which 


156  THE    MEANING    OF   EVOLUTION 

it  was  accomplished,  it  was  still  God's  plan  and  God 
carried  it  out. 

Now  that  we  have  tried  to  stretch  our  imagination 
back  to  the  origin  of  our  globe,  the  question  not  un- 
naturally comes  to  our  mind,  how  long  ago  did  all  this 
happen?  Is  there  any  possible  means  of  telling  when 
the  history  of  the  earth  began?  All  such  attempts 
lead  either  to  indefinite  or  to  uncertain  conclusions. 
Each  man  who  essays  the  problem  approaches  it  from 
a  different  side  and  ends  with  a  different  result.  But 
no  matter  what  the  method  of  approach,  all  are  agreed 
on  at  least  one  point,  the  enormous  length  of  time,  as 
counted  in  years,  through  which  the  earth  has  lasted. 

One  great  mathematician  worked  on  the  basis  of 
the  rate  of  the  present  cooling  of  the  earth.  Count- 
ing backward  to  the  time  when  the  earth's  surface 
must  have  been  hotter,  according  to  La  Place's  idea, 
he  decided  that  our  globe  has  been  cool  enough  for  the 
existence  of  life  upon  it  for  a  period  of  somewhere 
in  the  neighborhood  of  one  hundred  million  years. 
Those  who  try  to  study  the  rate  at  which  mud  is 
being  deposited  in  our  bays  and  at  the  mouth  of  our 
rivers,  and  who  hence  try  to  deduce  how  long  it  has 
taken  to  produce  the  thickness  of  all  the  stratified  rock 
we  know,  arrive  at  a  figure  larger,  rather  than  smaller, 
than  that  mentioned  above.  The  same  is  true  of  those 
who  try  to  count  the  age  of  the  earth  by  the  rate  at 


LIFE   IN    THE   PAST  iry 

which  the  present  rivers  are  carrying  away  their  river 
basins,  and  hence  who  calculate  how  long  it  has  taken 
the  rivers  of  the  globe  to  wash  away  all  the  rocks 
which  it  is  quite  clear  have  been  carried  out.  Still 
others  have  attempted  to  solve  the  problem  by  seeing- 
how  much  salt  the  rivers  are  carrying  into  the  sea, 
and  consequently  how  long  it  must  have  taken  the  sea 
to  become  as  salt  as  it  is.  A  very  late  attempt  has 
been  based  on  the  alteration  in  the  minerals  that  show 
radio-activity.  Conservative  estimates,  based  on  all 
of  these,  would  give  us  a  figure  on  which  we  must 
not  count  with  any  exactness,  but  which  will  serve  at 
least  to  mark  the  present  trend  of  opinion.  We  may 
put  this  figure  at  one  hundred  millions  of  years. 

The  following  table  gives  us  the  names  of  the 
periods  into  which  the  geologist  has  divided  the  past 
history  of  the  earth.  The  first  column  gives  a  simple 
name,  which,  in  each  case,  is  a  translation  of  the  tech- 
nical name  the  geologist  gives  to  the  era.  This  tech- 
nical name  is  also  given  in  parenthesis.  The  second 
column  shows  the  number  of  years  ago  at  which  this 
period  may  be  placed,  while  the  third  column  gives  a 
series  of  names  most  of  which  are  in  use  in  geology 
and  which  are  intended  to  indicate  the  stage  of  ad- 
vancement of  the  higher  animals  in  that  particular 
period.  Some  of  these  names  are  perhaps  giving  way 
to  later  terms,  but  all  of  them  will  be  understood  by 


•58 


THE    MEANING    OF    EVOLUTION 


any  geologist.  Most  of  them  will  serve  to  keep  very 
clearly  before  the  mind  of  the  ungeological  the  period 
which  he  is  studying.  Like  all  such  tables,  this  must 
be  read  from  the  bottom  up.  This  arrangement  is 
used  because  the  oldest  rocks  in  the  series  are  natu- 
rally at  the  bottom  and  the  newest  rocks  are  on  the 
top,  though  occasionally  a  region  is  sufficiently  upset 
partly  to  reverse  the  order. 

TABLE  OF  GEOLOGICAL  TIMES 


ERAS 

millions  of  years  ago 
(very  uncertain) 

stages  of  animal 
development 

Recent  Life 
(Cenozoic) 

o  to  5 

Age  of  Man 
(Quaternary) 

Age  of  Mammals 
(Tertiary) 

Middle  Life 
(Mesozoic) 

5  to  lo 

Age  of  Reptiles 

Ancient  Life 
(Palaeozoic) 

ID   to   25 

Age  of  Amphibians 
(Carboniferous) 

Age  of  Fishes 
(Devonian) 

Age  of  Invertebrates 
(Silurian  and  Cam- 
brian) 

Dawn  Life 
(Eozoic) 

25  to  50 

Earliest   Animals    and 
Plants 

Having  seen  what  the  scientist  supposes  to  be  the 
method  of    formation   of  the  earth   itself,   it  will  be 


LIFE    IN    THE   PAST 


159 


interesting  next  to  consider  what  the  biologist  sur- 
mises as  to  the  origin  of  the  Hfe  upon  the  earth. 
Here  again  two  explanations  hold.  The  one,  and  dis- 
tinctly the  older  of  the  two,  says  that  at  some  time 
in  the  far  distant  past,  under  conditions  which  are 
rarely  if  ever  duplicated,  out  of  the  lifeless  material 
of  the  globe  were  produced  simple  and  low  forms  of 
life.  These  could  not  properly  be  called  either  animal 
or  plant,  but  partook  somewhat  of  the  nature  of  both. 
Of  this  there  is  at  present  no  evidence  whatever.  The 
only  reason  we  have  for  suggesting  it  is  that,  if  we 
understand  the  past  conditions  on  the  earth,  there  was 
a  time  when  life  was  impossible.  Now  we  find  life. 
Hence  it  must  have  arisen.  This  of  itself,  of  course, 
furnishes  no  proof,  but  leads  us  to  try  to  imagine  how 
the  transition  might  have  come  about.  Every  scien- 
tist who  believes  in  this  form  of  origin  holds  that  if 
the  exact  conditions  are  repeated  the  result  will  occur 
once  more.  He  may  believe  that  no  such  repetition 
is  possible,  but  he  is  confident  that,  if  it  could  be,  life 
would  arise  again  from  lifeless  matter. 

This  process  of  life  arising  from  matter  that  is  not 
alive  is  known  as  Spontaneous  Generation.  Two  hun- 
dred years  ago  it  was  supposed  to  occur  frequently. 
It  was  common  belief  that  the  beautiful  pickerel  weed 
which  borders  our  Northern  lakes,  after  freezing,  went 
into  a  sort  of  protoplasmic  slime  out  of  which  pick- 


l6o  THE   MEANING   OF   EVOLUTION 

erel  were  produced.  The  eclgrass  of  the  river  was 
supposed  to  yield  eels  in  a  similar  fashion.  The  dead 
bodies  of  animals  were  supposed  to  turn  into  mag- 
gots. Such  crude  ideas  of  spontaneous  generation 
are  no  longer  possible.  The  whole  science  of  bacteri- 
ology absolutely  presupposes  the  impossibility  of  spon- 
taneous generation  in  the  flasks  and  test  tubes  of  the 
lal)oratory.  One  or  two  men  of  otherwise  good  stand- 
ing in  science  still  maintain  that  they  are  getting  new 
life  in  their  own  test  tubes,  but  they  fail  utterly  to 
persuade  the  scientific  world.  I  think  it  is  a  fair  state- 
ment of  the  position  of  science  to-day  to  say  that  there 
is  no  evidence  whatever  of  spontaneous  generation, 
excepting  the  presence  of  life  upon  the  globe. 

Not  all  has  been  said,  however,  on  this  question. 
The  chemist  is  learning  in  the  laboratory  to  produce 
many  substances  which,  until  very  recent  times,  were 
produced  only  in  the  bodies  of  animals  or  plants.  Dye- 
stuffs  were  originally  gotten  almost  entirely  from  ani- 
mal or  plant  material.  At  present  the  great  majority 
of  them  are  made  in  the  laboratory,  and  in  not  a  few 
cases  they  not  only  imitate  the  color  of  the  older  ma- 
terial, but  actually  have  identically  the  same  compo- 
sition and  constitution.  The  laboratory-made  mate- 
rial is  exactly  like  that  made  by  the  animals  or  the 
plants. 

The  same  is  true  with  regard  to  a  large  number  of 


LIFE   IN    THE   PAST  l6l 

the  fruit  flavors.  These  are  due  to  the  presence  of 
ethereal  oils  in  the  plant,  and  their  exact  counter- 
parts can  now  be  produced  in  the  laboratory,  and  can 
serve  every  purpose  of  the  fruit  flavor  itself.  Alcohol 
has  been  produced  artificially,  and  alcohols,  which  na- 
ture never  dreamed  of  making,  so  far  as  we  can  tell, 
but  which  are  made  on  her  plan,  are  manufactured  by 
the  chemist.  Last  of  all,  sugar  has  recently  been 
built  up  by  the  chemist,  though  the  method  at  present 
is  so  expensive  that  it  cannot  possibly  compete  with 
the  production  of  the  commodity  from  the  cane  and 
the  beet.  As  in  the  case  of  alcohol,  all  the  sugars  that 
nature  makes  can  now  be  made  artificially,  and  others 
of  the  same  general  plan  which  she  seems  not  to  have 
as  yet  devised  can  be  produced  within  the  laboratory. 

Attempts  have  been  made  to  manufacture  proteids, 
but  these  have  as  yet  eluded  the  efforts  of  the  chemist. 
He  is  beginning,  however,  to  come  nearer  understand- 
ing their  composition,  and  when  he  once  clearly  com- 
prehends that  he  may  be  able  to  reproduce  them. 

One  of  the  German  chemists  is  convinced  that  the 
nuclein  in  the  nucleus  of  the  cell  is  not  a  very  compli- 
cated compound.  Under  such  conditions  it  is  not  a 
matter  of  surprise  that  the  physiological  chemist 
should  be  constantly  dreaming  that  he  may  at  some 
time  produce  living  matter  in  the  laboratory.  To  the 
ordinary  mind  it  scarcely  seems  possible.     We  are  so 


l62  THE    MEANING    OF    EVOLUTION 

entirely  sure  that  life  is  not  amenable  to  physics  or 
chemistry  that  we  can  hardly  conceive  of  the  possi- 
bility of  its  originating  out  of  matter  in  the  test  tube. 
If  it  does  so  come,  and  when  it  does  so  come,  this 
will  not  prove  that  life  is  a  less  noble  and  less  wonder- 
ful thing  than  we  thought.  It  will  only  prove  that 
chemistry  and  physics  are  more  noble  and  more  won- 
derful than  we  dreamed. 

There  is  another  way  of  approaching  this  life  prob- 
lem, though  it  seems  to  be  rather  a  begging  of  the 
question  than  a  solution  of  it.  Of  recent  years  it  has 
been  discovered  that  even  the  very  low  temperatures 
obtained  by  evaporating  liquid  air,  say  three  hundred 
degrees  below  zero,  Fahrenheit,  do  not  kill  seeds  or 
spores  of  mold.  The  space  between  the  planets  is  un- 
doubtedly extremely  cold.  We  have  always  supposed 
it  to  be  entirely  too  cold  for  life  to  exist  in  it.  But 
we  laid  little  stress  on  the  fact  because  we  had  no 
thought  of  any  possible  life  existing  there.  But  the 
discovery  that  seeds  and  spores  can  live  uninjured 
through  extreme  cold  has  led  to  an  interesting  sug- 
gestion. This  is  that  when  the  earth  became  adapted 
to  the  presence  of  life  it  was  infected  by  germs  trans- 
ported on  meteors  from  some  other  system.  Accord- 
ing to  this  theory,  organic  dust  through  space  is  ready 
to  infect  any  planet  which  offers  the  conditions  under 
which  life  may  arise.     Of  course  this  theory  does  not 


LIFE    IN    THE    PAST  163 

explain  the  origin  of  life.  It  pushes  back  that  origin 
a  little  farther  or  supposes  that  life  is  as  old  as  matter 
itself.  Again  we  may  leave  to  the  scientist  the  dis- 
cussion and  the  elaboration  of  this  or  any  other  theory 
he  may  promulgate  concerning  the  origin  of  life. 
When  he  has  established  clearly  the  process  and  can 
produce  life  we  will  accept  his  explanation ;  mean- 
while, we  will  always  be  interested  in  his  attempts  to 
solve  the  problem,  but  still  our  simple  formula,  "in 
the  beginning  God,"  serves  our  present  needs  and  will 
satisfy  us  better  than  any  as  yet  unverified  hypothesis. 

When  we  find  through  scientific  investigation  how 
life  arises  we  will  simply  know  how  God  created  it 
in  the  beginning. 

The  next  step  in  the  understanding  of  early  life  is 
to  study  under  the  microscope  the  simplest  forms 
which  we  can  find  in  existence  to-day.  This,  while 
far  easier  of  execution  than  the  problems  which  we 
have  thus  far  considered,  is  still  not  without  serious 
difiicuUies.  But  every  day  brings  us  nearer  to  the 
understanding  of  the  structure  of  living  things.  Life 
the  scientist  cannot  see.  All  he  can  study  is  living 
matter.  Whether  life  can  exist  separate  from  living 
things  is  a  problem  outside  the  range  of  his,  at  least 
present,  possibilities.  Therefore,  concerning  it  he  has 
no  answer  whatever  to  give.  But  when  we  come  to 
study  living  things  we  find  that  all  life  is  associated 


164  THE    MEANING   OF   EVOLUTION 

with  protoplasm.  This  apparently  foamy,  jcllylike, 
transparent  material  is  the  only  living  substance  in 
all  the  world.  Animals  and  plants  are  larger  or 
smaller  collections  of  the  little  masses  of  protoplasm 
which  we  know  as  cells.  The  lowest  animals  are  each 
made  up  of  but  a  single  cell.  This  consists  of  a 
small  mass  of  protoplasm  surrounded  almost  always 
by  a  thicker  skin  or  covering,  known  as  the  cell  wall 
and  enclosing  a  complicated  kernel  known  as  the  nu- 
cleus. The  protoplasm  seems  to  be  the  living  sub- 
stance itself.  The  cell  wall  is  not  a  simple  dead  scum 
on  the  outside  of  the  protoplasm,  but  is  itself  able  to 
do  certain  things  which  can  only,  so  far  as  we  know, 
be  done  by  living  substances.  For  instance,  of  two 
materials  dissolved  in  the  water  in  which  the  cell 
floats,  the  wall  may  permit  one  to  soak  into  the  ani- 
mal and  keep  the  other  out.  The  one  allowed  to 
enter  will  usually  be  found  good  to  be  used  for  food 
by  the  cell.  The  nucleus  seems  to  store  within  itself 
the  record  of  its  past  history  and  thus  enable  the  cell 
to  do  in  the  future  what  its  ancestors  did  in  the  past. 
Such  simple  cells  can  exhibit  in  very  low  form  all 
the  activities  the  higher  animals  show  in  much  more 
elaborate  development.  A  one-celled  animal  can  move 
about,  can  recognize  the  proximity  of  food,  can  en- 
gulf its  food  and  digest  it,  can  build  up  its  own  sub- 
stance out  of  the  digested  food,  can  absorb  oxygen, 


LIFE   IN    THE   PAST  1 65 

can  use  this  oxygen  in  the  burning  of  its  own  sub- 
stance to  produce  its  own  activities,  can  act  in  re- 
sponse to  sensation  gained  from  outside,  can  throw 
off  its  waste  matter  produced  by  its  own  activities,  and 
can  grow.  When  the  proper  time  comes  its  nucleus 
can  spHt  in  two,  the  cell  itself  enclosing  the  nucleus 
can  separate  into  two  cells,  each  of  which  can  grow 
to  the  size  of  the  parent  cell  and  repeat  its  life.  This 
is  as  simple  an  animal  as  we  have  yet  discovered. 
Every  kitchen  drain  swarms  with  such  creatures.  On 
a  summer  day  the  stagnant  pools  are  full  of  them. 
The  simplest  microscope  will  show  them  clearly.  This 
is  life  in  its  lowest  terms  with  which  we  are  ac- 
quainted. With  such  life,  it  seems  to  us,  the  animal 
and  plant  world  must  have  started  their  existence, 
when  first  the  earth  began  to  teem  with  living  matter. 
If,  then,  we  may  form  any  judgment  concerning  the 
first  living  things  upon  the  globe  by  considering  the 
simplest  creatures  that  live  here  to-day,  certain  facts 
seem  clear.  In  the  first  place,  life  began  in  the  water, 
and  for  a  long  time  was  only  to  be  found  in  the  water. 
Single  cells  are  so  small  and  dry  out  so  easily  that 
it  is  necessary  to  their  existence  that  they  should  be 
kept  entirely  moist  by  the  presence  of  water  all  about 
them.  It  is  true  many  of  them  will  stand  drying,  but 
while  they  are  thus  dried  they  can  scarcely  be  said  to 
be  much  more  than  just  alive.     They  are  utterly  in- 


l66  THE    MEANING    UF    EVOLUTION 

active,  or,  as  wc  say,  they  are  dormant.  In  such  con- 
ditions they  become  covered  with  a  tough  skin,  ahnost 
a  shell,  and  their  protoplasm  is  itself  nearly  dry. 
Under  these  circumstances  the  life  processes  hardly 
continue  at  all.  The  protozoa,  as  these  small  animals 
arc  called,  tolerate  drought  for  a  time ;  but  they  only 
live,  in  any  sense  worth  calling  living,  wdien  water  is 
abundant  and  is  neither  very  warm  nor  very  cold. 
It  is  safe  to  say  that  the  early  life  of  the  world  formed 
in  the  oceans  of  the  time.  So  absolutely  is  the  habit 
fixed  upon  cells  of  protoplasm  that  even  to-day  the 
activities  of  the  cells  of  higher  animals  depend  upon 
the  presence  of  moisture.  The  cells  of  our  ow^n  bodies 
are  to-day  living-,  as  it  were,  in  an  ocean.  Everyone 
can  remember  far  enough  back  to  recall  some  time  at 
which  a  tear  slipped  from  his  own  eye  onto  his  own 
tongue ;  we  know  our  tears  are  salt.  The  tongue  has 
tasted,  undoubtedly,  the  perspiration  from  the  lip  on 
more  than  one  summer  day ;  this  perspiration  tasted  as 
salt  as  the  tear  itself.  The  lymph  that  constitutes  the 
"water"  of  a  so-called  ''water  blister"  is  also  salty, 
and  even  the  little  blood  one  gets  into  his  mouth  in 
trying  nature's  method  of  stanching  the  flow  from  a 
cut  finger  gives  the  impression  that  it  contains  a  little 
salt.  Every  fluid  of  the  body  is  salty,  and  every  cell 
of  the  body  is  bathed  in  salt  water.  It  is  too  long 
since  the  ancestors  of  our  cells  swam  in  the  seas  of  the 


LIFE   IN    THE   PAST  1 67 

Eozoic  time  for  us  to  assert  with  any  positivcness  that 
the  ancestral  habit  is  responsible  for  this  trait  in  the 
descendants.  Sure  it  is  that  to-day  our  cells,  like  their 
ancestors  of  old,  live  in  water,  and  this  water  is 
slightly  salty — as  were  probably  the  Archaean  seas. 

The  geologist  tries  as  best  he  may  to  build  up  the 
geography  of  the  earth  in  the  past.  He  endeavors  to 
judge  from  the  rocks  as  he  now  finds  them,  where  the 
seas,  the  bays,  the  dry  land,  and  the  mountains  of 
earlier  geological  times  lay.  The  present  aspect  of 
the  earth  is  very  recent,  and  earlier  ages  must  have 
shown  an  entirely  different  distribution  of  land  and 
water.  The  North  American  continent  was  certainly 
very  much  smaller  than  it  is  now.  The  first  known 
lands  lay  close  to  the  Atlantic  seaboard  and  probably 
extended  out  into  the  water  some  distance  beyond  the 
present  shoreline.  The  stretch  of  continent  was  nar- 
row, and  grew  narrower  as  it  went  southward.  In 
what  is  now  the  Canadian  district,  a  considerable 
expanse  probably  existed  in  very  early  times.  Then 
a  great  internal  sea,  shallower  than  the  Atlantic, 
stretched  its  unbroken  sheet  over  almost  the  entire 
area  now  occupied  by  the  United  States,  while  only  a 
comparatively  small  hump  of  earth,  ending  in  a  nar- 
rower strip,  lay  where  the  great  Western  plateau  now 
rears  its  enormous  bulk. 

A  large  portion  of  the  history  of  the  North  Amer- 


l68  THE    MEANING   OF   EVOLUTION 

ican  continent,  with  its  developing  animals  and  plants, 
is  tied  up  with  the  gradual  shrinkage  of  this  interior 
sea.  Slowly  across  the  Canadian  district,  the  Eastern 
and  Western  lands  became  connected  with  each  other, 
while  the  waters  progressively  were  pushed  down  the 
continent,  which  was  steadily  growing  from  the  east 
and  from  the  north,  though  less  slowly  from  the  west, 
into  this  internal  sea.  To-day  only  the  Gulf  of  Mex- 
ico remains  as  evidence  of  the  broad  stretch  that  once 
extended  through  to  the  Arctic  Ocean  and  west  be- 
yond the  present  position  of  the  Rocky  Mountains. 

How  this  great  Eastern  backbone  of  the  continent 
was  produced,  what  sort  of  animals  lived  while  these 
rocks  were  being  formed,  or  whether  this  preceded 
entirely  the  existence  of  life  upon  the  earth,  no  man 
to-day  may  surely  say.  In  the  oldest  of  the  rocks 
there  are  beds  of  graphite,  from  which  lead  pencils  j 
are  made.  This  substance  is  believed  by  the  geolo- 
gists to  be,  like  coal,  the  remains  of  vegetable  life. 
But  these  early  rocks  have  been  so  heated  and  baked, 
so  twisted  and  bent,  that  whatever  forms  of  life  they 
once  held  are  now  obliterated,  or  so  altered  as  to  give 
us  no  idea  of  what  may  have  been  their  character. 

So  far  as  anyone  can  now  see,  this  past  history  is 
wiped  out  forever  and  it  will  be  impossible  for  men 
ever  to  demonstrate  the  character  of  this  early  life. 
Speculations,  more  or  less  certain,  will  arise.     They 


LIFE  IN    THE   PAST  1 69 

may,  after  a  while,  seem  so  clear  as  to  receive  the 
acceptance  of  the  scientific  mind.  Yet  the  truth  re- 
mains that  the  early  history  of  the  earth,  so  far  as 
animals  and  plants  are  concerned,  is  probably  lost 
forever. 

The  most  striking  feature  concerning  the  earliest 
layers  of  rocks  in  which  good  fossils  are  found  abun- 
dantly is  the  complexity  of  the  life.  With  the  excep- 
tion of  the  backboned  anihials,  every  important  branch 
of  the  animal  kingdom  is  represented,  and  it  is  just 
possible  that  w^e  have  even  earlier  forms  of  the  verte- 
brates themselves.  This,  to  the  evolutionist,  is  very 
disconcerting.  To  find  the  great  groups  all  well  de- 
veloped at  least  twenty-five  million  years  ago  and  to 
find  only  fossils  built  on  the  same  lines  since  almost 
nonplusses  him.  When  the  geologist  tells  him  what 
an  enormous  length  of  time  preceded  the  rocks  in 
which  he  finds  these  fossils  and  how  absolutely  these 
earlier  strata  have  been  altered  by  the  later  geologi- 
cal activities  he  easily  understands  why  it  is  impos- 
sible to  find  fossils  in  them.  As  a  consequence,  the 
evolutionist  is  forced  to  believe  that  all  the  earliest 
animals  have  left  no  clear  traces  behind  them.  Life 
as  he  first  surely  knows  it  is  already  extremely  varied 
and  quite  well  developed  in  some  of  its  groups.  1  he 
early  animals  were  as  well  adapted  to  the  times  in 
which  they  lived  as  are  the  great  majority  of  the  ani- 


IJO  THE    MEANING    OF    EVOLUTION 

nials  of  to-day.  The  reader  must  not  infer  this  to 
mean  that  the  animals  of  those  days  were  Hke  our 
l)rescnt  animals.  They  were  not.  No  one  traveling 
in  a  far  country  could  find  there  animals  as  strange  to 
him  as  would  he  those  of  the  earlier  stratified  rocks. 
In  these  there  were  no  fishes  as  we  know  them  to- 
day, not  a  single  member  of  the  frog  and  salamander 
class,  not  a  reptile,  not  a  bird,  not  a  mammal,  and 
probably  no  air-living  insects.  It  is  highly  doubtful 
whether  there  was  any  animal  living  upon  the  land 
and  breathing  the  air  twenty-five  million  years  ago. 

We  start  our  study,  then,  at  the  period  known  as 
the  Palaeozoic  era,  the  era  of  the  ancient  life  of  the 
globe,  beginning  twenty-live  million  and  ending  ten 
million  years  ago.    The  first  of  the  three  sections  into 
which  this  period  of  life  is  divided  is  known  as  the 
Silurian  age,  the  age  of  invertebrates.     The  word  in- 
vertebrate is  an  unscientific  but  convenient  term  under 
which  we  embrace  all  the  animals  below  those  having 
backbones.     This  period  is  called  the  age  of  inverte- 
brates because,  although  there  is  an  enormous  wealth 
of  animal  and  plant  life  in  the  Silurian,  there  are  no 
backboned  animals  except  the  lowest  kinds  of  fishes. 
It  was  supposed  for  a  long  time  that  even  fishes  were 
absent.     Now  we  know  they  existed,  but  they  were 
small  and  inconspicuous.     In  this  period  corals  were 
wonderfully  abundant,  particularly  in  the  great  inter- 


LIFE   IN    THE    PAST  I7I 

nal  sea  which  spread  over  what  is  now  known  as  the 
Mississippi  Valley.  Everywhere  over  this  region  must 
have  grown  in  the  shallow  water  great  numbers  of 
creatures  called  crinoids  or  stone  lilies.  They  were 
attached  to  the  bottom  by  slender  stems,  sometimes 
many  feet  long.  These  stems  are  jointed,  and  when 
they  became  fossilized  the  sections  were  apt  to  sepa- 
rate, with  the  result  that  over  a  wide  area  in  the 
Mississippi  Valley  it  is  very  common  to  find  these 
little  segments  which  look  not  unlike  checkers.  At  the 
end  of  the  stem  was  a  rounded  head,  with  a  mouth 
at  the  top,  and  around  the  mouth  were  branched, 
feathery  arms.  The  creatures  must  have  been  ex- 
quisitely beautiful,  but  they  have  completely  disap- 
peared from  the  face  of  the  earth,  with  the  exception 
of  a  very  few,  found  in  the  obscurity  of  the  almost 
fathomless  depths  of  the  great  ocean.  Here  they 
remain  as  peculiar  relics,  only  preserved  by  the  un- 
varying conditions  in  the  deep  sea  from  the  extinc- 
tion that  has  met  their  sisters. 

Those  who  are  familiar  with  our  seacoast  will  know 
an  interesting  creature  known  as  the  horseshoe  crab, 
or  king  crab,  though  in  reality  it  is  not  a  crab  at  all. 
It  is  rather  more  nearly  related  to  the  spiders  than 
the  crabs,  though  no  one  but  a  technical  zoologist 
could  possibly  associate  them  together.  The  ancestors 
of  these  king  crabs  were  the  finest  and  best  devcl()i)cd 


T72  THE    MEANING    OF    EVOLUTION 

animals  in  this  early  PaLxozoic  time.  These  creatures 
had  hodies  jointed  like  the  tail  of  a  lohster.  They 
were  wide  and  flat,  instead  of  narrow  and  rounded 
like  a  lobster,  and  each  joint  of  the  body  was  highest 
in  the  middle  and  distinctly  lower  at  the  two  sides, 
thus  forming  three  regions  along  their  backs.  This 
structure  gives  to  these  creatures  the  name  of  trilo- 
bites.  These  animals  were  the  kings  of  the  early 
ocean.  They  had  an  interesting  habit  of  curling  up 
nose  to  tail  before  they  died,  and,  as  a  result,  a  large 
proportion  of  all  the  trilobite  fossils  we  find  are  curled 
in  this  peculiar  manner. 

After  these  forms  the  most  abundant  fossils  we 
find  in  Silurian  times  were  creatures  that  at  first  sight 
looked  as  if  they  might  be  related  to  the  clams.  These 
are  known  as  lampshells,  because  one  shell  projects 
beyond  the  other  and  curls  up  at  the  tip  so  as  to  re- 
semble the  clay  lamps  which  are  dug  out  of  old  Roman 
towns.  The  lampshells  also  have  nearly  disappeared 
in  modern  times.  Simple  creatures  belonging  with 
our  present  crab  and  snail  had  begun  to  make  their 
appearance,  but  they  were  not  as  abundant  as  we  find 
them  later  on. 

The  third  group  of  the  mollusks  to  which  the  nau- 
tilus and  squid  of  to-day  belong  is  very  abundantly 
represented  in  the  Silurian  by  fossils  with  coiled-up 
shells.     As  for  the  plant  life  of  the  time,  it  is  exceed- 


LIFE   IN    THE   PAST  I^^ 

ingly  difficult  to  say  much  about  it.  There  must  have 
been  nothing  but  marine  plants,  and  these  must  have 
been  on  the  general  line  of  the  seaweeds.  Little  can 
be  definitely  said  concerning  them. 

The  next  period  of  the  Palaeozoic  is  known  as  the 
Devonian  age,  or  the  age  of  fishes.  Now  the  back- 
boned animals  first  make  their  clear  and  unmistakable 
appearance.  There  are  remains  in  the  Silurian  which 
show  that  there  must  have  been  a  few  fishes  at  that 
time.  The  Devonian  is  so  full  of  them  and  they  are 
so  well  developed  and  so  diversified  that  this  period 
is  definitely  known  as  the  "age  of  fishes."  They  do 
not  closely  resemble  the  fishes  of  to-day,  but  anyone 
would  recognize  most  of  them  for  what  they  are. 
Their  bodies  were  covered,  not  so  much  with  scales  as 
with  heavy  plates,  often  arranged  like  tiles,  those  on 
the  forward  half  of  the  animal  being  often  larger 
than  those  surrounding  the  rest  of  the  body.  The 
creature  was  encased,  as  it  were,  in  armor.  These 
were  the  rulers  of  the  Devonian  seas.  The  land,  as 
yet,  was  probably  nearly  without  animal  life,  the 
creatures  thus  far  being  almost  confined  to  the  water. 
A  few  insects  make  their  appearance  and  a  few  thou- 
sand-leggers  are  running  around  among  the  lowly 
plants;  a  few  spider-like  animals  have  arisen;  there 
are  a  few  snails  that  have  left  the  water  and  taken 
to  the   land.     Altogether  only  the  dawn  of  a  land 


174  THE   MEANING   OF   EVOLUTION 

fauna  is  to  be  noticed.  In  the  Devonian  the  plants 
are  creeping  up  upon  the  ground.  Ferns  are  growing 
about  everywhere,  though  they  are  not  exactly  our 
ferns,  but  are  rather  a  sort  of  intermediate  form  be- 
tween these  and  the  present  seed  plants. 

Now  comes  an  entire  change  in  the  history  of  the 
w^orld.  By  some  means  a  rise  in  the  bottom  seems 
to  have  cut  off  a  great  part  of  the  internal  sea  from 
the  outer  ocean  and  to  have  converted  it  into  a  wide- 
spread shallow  bay,  much  like  the  sounds  which  lie 
back  of  the  islands  that  line  the  Atlantic  Coast  from 
New  Jersey  to  Florida.  Just  as  this  coastal  region 
to-day  is  covered  with  salt  marshes,  so  the  whole  in- 
ternal sea  of  the  Carboniferous  period  was  converted 
into  a  great  swamp.  Sometimes  an  oscillation  of  the 
crust  of  the  earth  brought  this  marsh  above  the  sur- 
face of  the  sea  and  a  luxuriant  growth  of  plants 
spread  over  it.  Then  a  sinking  of  the  bottom  allowed 
the  mud  and  sand  to  wash  down  the  shores,  and  spread 
out  over  the  marsh,  and  enclose  the  muck  of  the 
marsh  under  a  layer  of  sand  or  clay.  Another  lift 
of  the  bottom  would  start  the  swamp  growing  once 
more,  and  a  series  of  alternations  between  marsh  land 
and  sound  seems  to  have  followed.  The  plants  of 
this  period  are  not  the  plants  of  to-day,  though  we 
still  have  some  very  degenerate  representatives  of 
them.      The    common    horse-tail,    with    its    angular. 


LIFE   IN    THE    PAST  1 75 

slender,  leaflike  branches  and  its  club-shaped  spore- 
bearing  body,  is  a  modern  degenerate  descendant  of 
the  treelike  calamites  of  the  Carboniferous  forest.  A 
creeping  evergreen,  known  by  the  name  of  clubmoss, 
is  in  like  manner  the  modern  degenerate  remnant  of 
the  scalestem  and  sealstcm,  which  were  the  great  trees 
of  the  forests  of  the  coal  period. 

All  over  the  surface  of  the  marsh,  between  these 
big  trees,  grew  the  ferns.  While  the  coal  itself  was 
formed  generally  from  the  scalestems  and  sealstems, 
the  most  common  fossils  found  in  the  shales  that  lie 
upon  the  coal  beds  are  the  ferns  which  covered  the 
surface  of  the  marsh. 

It  is  believed  by  many  geologists  that  this  great 
luxuriant  forest  points  to  a  time  when  the  climate 
was  far  warmer  than  it  is  to-day,  when  the  air  was 
moist  and  heavily  laden  with  carbon  dioxide,  and 
when  a  great  mass  of  clouds  practically  enveloped  the 
earth.  In  this  way  only  do  most  geologists  account 
for  the  enormous  wealth  of  vegetation  in  the  Car- 
boniferous period  and  for  the  abundance  of  plants  up 
to  the  Arctic  Ocean,  of  the  kinds  that  now  grow 
chiefly  in  the  tropics.  But  of  recent  years  a  few 
geologists  point  to  the  fact  that  the  peat  bogs  of  to- 
day, which  seem  to  be  the  beginnings  of  future  coal 
deposits,  are  found  almost  entirely  in  cold  countries. 
Hence  it  is  a  serious  matter  to  attempt  to  describe 


176  THE   MEANING   OF   EVOLUTION 

the  climate  of  any  part  of  the  Palaeozoic  era.  Cer- 
tainly of  the  climate  earlier  than  the  Carboniferous  it 
is  very  risky  to  say  anything  definite. 

The  forests  of  the  coal  period  seem  actually  to 
have  cleared  the  air;  at  least  now  we  begin  to  find 
creatures  related  to  our  salamanders  and  frogs  moving 
about  among  the  stumps  of  the  marshes.  These  am- 
phibians are  evidently  the  descendants  of  some  of  the 
fishes  of  the  Devonian  times.  Among  these  fishes 
were  some  which  bear  a  great  resemblance  to  a  few 
found  in  South  America,  in  Africa  and  Australia  to- 
day, and  which  we  know  as  lungfish.  Anyone  who 
has  cleaned  our  fresh  water  fishes  in  preparation  for 
the  table  will  remember  that  inside  of  them  there  is  a 
long  slender  bladder  filled  with  air.  This  bladder 
assists  in  making  the  fish  light,  hence  making  it  easier 
for  it  to  support  itself  in  the  water.  In  certain 
swampy  regions  these  lungfish  swim  freely  in  the 
water  of  the  marshes.  When  the  dry  season  comes, 
however,  the  water  evaporates,  draining  the  marshes 
completely.  This  would  prove  the  death  of  most 
fishes.  The  lungfish  have  a  curious  habit  which  keeps 
them  over  the  dry  season.  They  cover  themselves 
with  a  coat  of  mud,  inside  of  which  there  is  a  lining 
of  slime  produced  from  their  bodies.  In  such  cocoon- 
like cases  they  survive  the  drought.  The  means  by 
which  they  breathe  during  this  dry  season  is  inter- 


LIFE   IN    THE   PAST  1 77 

esting".  The  swim-bladder  which  we  have  just  de- 
scribed in  other  fishes  is,  with  this  hingfish,  pecuharly 
spongy  in  its  walls,  presenting  a  large  surface  full  of 
blood  vessels  which  absorb  the  air  on  the  inside  of 
the  bladder.  This  air  the  fish  changes  with  moderate 
frequency,  the  result  being  that  the  swim-bladder 
serves  him  exactly  as  the  lung  serves  a  higher  animal. 
To  this  fact  he  owes  his  name  of  lungfish. 

We  sometimes  gain  much  light  concerning  the  past 
history  of  any  particular  form  of  animal  by  studying 
the  development  of  that  animal  in  the  egg,  or,  in  the 
case  of  the  mammals,  before  birth.  It  is  an  interest- 
ing fact  that  when  the  lung  begins  to  form  in  the 
embryo  it  starts  as  a  simple  sac  which  is  an  offspring 
from  the  gullet,  and  occupies  the  position  of  the  swim- 
bladder  of  the  fish.  This  sac  later  divides  into  two, 
and  develops  into  the  lungs  of  the  animal.  This 
assures  the  zoologist  that  the  origin  of  the  lungs  in 
the  higher  animals  is  found  in  the  swim  bladder  of 
the  so-called  lungfish.  In  this  Silurian  time  certain 
of  these  lungfish  were  perhaps  trapped  in  the  basin  in 
the  marsh  by  the  uplifting  of  the  border.  The  waters 
becoming  progressively  shallower  and  more  crowded, 
these  fishes  took  to  the  land,  their  fins  developing  into 
awkward  limbs  which  slowly  became  more  perfect. 

To  state  the  fact  in  this  simple  fashion  is  to  make 
it  seem  far  less  probable  than  is  really  the  case.    The 


178  THE    MEANING    OF    EVOLUTION 

simple  forms  of  the  life  of  lowly  creatures,  as  well 
as  the  simple  character  of  the  legs  and  feet  in  the 
salamander  class,  make  the  explanation  not  so  un- 
likely as  would  at  first  sight  appear.  Suffice  it  to  say 
that  the  scientist  now  believes  that  out  of  the  lung- 
fish  of  the  Devonian  came  the  amphibians  of  the  Car- 
boniferous period. 

At  the  end  of  the  coal  period  came  the  greatest 
change  the  face  of  the  globe  had  seen  for  many  mil- 
lions of  years.  Slowly  the  continent  rose  on  both 
sides  of  the  old  interior  sea.  A  great  plateau  formed 
in  the  region  of  the  Alleghenies  and  another  in  the 
western  district,  though  this  latter  uplift  was  to  be 
completely  washed  away,  and  later  to  rise  again  into 
the  Rocky  Mountains  and  the  Sierras.  With  the  up- 
lift at  the  edges  of  the  continent  came  a  steady  rise  of 
the  internal  marshes,  until  what  had  previously  been 
swamp  land  became  progressively  first  dry  land  and, 
in  the  western  part,  even  desert,  in  that  respect  being 
somewhat  like  what  it  is  now. 

The  amphibians  of  to-day  (animals  like  the  sala- 
mander and  frog)  all  lay  their  eggs  in  the  water 
and  their  young  have  a  tadpole  stage.  This  doubtless 
was  true  of  the  amphibians  of  the  coal  period.  With 
the  beginning  of  the  Mesozoic,  or  "middle  life" 
period,  a  change  and  a  progression  comes  over  the 
animal  world.    The  tadpole  life  of  the  frog  is  a  rather 


LIFE   IN    THE    PAST 


179 


lengthened  one,  while  the  toad  has  learned  to  crowd 
its  tadpole  life  within  a  few  weeks.  It  would  seem 
as  if,  in  the  earlier  times  of  the  Mesozoic,  this  same 
change  of  habit  had  been  going  on.  With  the  dryin^-- 
up  of  the  swamp,  some  of  the  amphibians  crowded 
their  tadpole  stage  further  and  further  back,  until  it 
was  completely  accomplished  before  their  young  left 
the  egg.  An  examination  of  the  development  of  the 
reptile  in  the  egg  will  show  a  stage  very  similar  to 
the  fish  and  to  the  amphibians,  but  this  is  all  experi- 
enced before  the  reptile  emerges  from  the  Qgg.  The 
reptilian  egg,  unlike  that  of  the  frog,  is  covered  with 
a  shell,  packed  away  under  the  surface  of  the  ground, 
and  left  to  its  own  fate.  If,  as  most  geologists  be- 
lieve, the  climate  of  the  Mesozoic  was  distinctly  warm, 
this  habit  of  the  parent  of  forsaking  the  egg  was  not 
a  serious  matter.  However  the  creatures  arose,  it  is 
certain  that  in  this  Mesozoic  age  reptiles  roamed  the 
forests,  swam  the  seas,  and  even  flew  in  the  air. 
Probably  at  no  other  time  in  the  earth's  history  has 
any  one  class  of  animals  so  completely  dominated  the 
situation  as  did  the  reptiles  of  this  age.  They  were 
not  only  abundant;  they  were  frequently  enormously 
large.  Their  skeletons  are  among  the  most  interesting 
that  we  find  to-day.  Gigantic  lizards,  seventy  feet 
long  and  eighteen  feet  high  at  the  shoulders,  dragged 
their  heavy  bodies  through  the  marshy  edges  of  the 


l8o  THE    MEANING   OF    EVOLUTION 

lakes.  Out  upon  the  land  others,  not  quite  so  heavy 
nor  so  larg-e,  roamed  about,  some  of  them  feeding 
upon  the  soft  vegetation,  others  having  teeth  fitted  to 
tear  down  their  herbivorous  cousins.  In  some  of  them 
the  hind  legs  and  tail  were  very  heavy  and  the  front 
legs  so  light  that  it  is  quite  clear  they  must  have 
hopped  around  as  do  the  kangaroos  to-day.  Others  of 
these  reptiles  went  back  to  the  sea,  lost  the  leglike 
development  of  their  limbs  and  regained  the  Hipper 
form,  though  the  bones  of  the  fingers  and  toes  are 
singularly  distinguishable  in  the  paddle. 

Strangest  of  all,  a  considerable  group  of  these 
wonderful  reptiles  lengthened  their  little  fingers,  some- 
times to  three  or  four  feet  in  length,  and  had  a  skin 
stretched  from  these  fingers  over  to  the  body  in  such 
a  fashion  as  to  give  them  wings  not  unlike  those  of 
the  bat.  In  the  wing  of  the  bat,  however,  four  of 
the  fingers  of  the  hand  run  through  the  membrane  and 
support  it.  In  the  pterodactyl,  as  these  flying  reptiles 
are  called,  the  middle  finger  supports  the  web,  while 
the  remaining  fingers  can  still  be  used  to  clasp  objects 
or  serve  the  animal  to  lift  himself,  as  the  bat  can  do 
with  his  thumbs. 

IMeanwhile  an  entire  change  is  coming  over  the 
plant  world.  The  last  third  of  this  age  of  reptiles  is 
known  as  the  Cretaceous  or  chalk  period.  Now,  for 
the  first  time,  the  forests  begin  to  take  on  more  of 


Y 


LIFE  IN   THE  PAST  l8l 

the  character  of  our  forests  of  to-day.  Plants  like 
our  willow  and  beech,  poplar  and  sassafras  appear  in 
great  abundance.  Their  broad  leaves  serve  better 
than  those  of  any  earlier  plants  to  catch  the  sunlight. 
But  in  addition  they  offered  such  effective  evaporat- 
ing surface  that  they  cast  off  rapidly  the  moisture 
obtained  from  the  ground  by  the  plant.  Accordingly 
in  the  winter  season,  when  the  water  in  the  ground 
is  frozen  and  not  available  for  plant  purposes,  they 
were  forced  to  throw  away  their  leaves.  It  is  quite 
possible  that  up  to  and  including  the  time  of  the  Car- 
boniferous, plants  were  all  evergreen.  There  had 
been  before  this  little  variation  in  climate  over  the 
globe.  Life  in  the  Cretaceous  begins  to  take  on  dis- 
tinctly its  modern  form. 

Among  the  reptiles  of  the  forest  there  appear  to 
have  been  a  few  small  creatures  which  to  an  observer 
of  those  times,  if  there  could  have  been  an  observer, 
would  have  seemed  of  the  utmost  insignificance  com- 
pared with  their  giant  cousins. 

These  little  creatures  climbed  up  into  the  trees  to 
escape  their  enemies.  There  were  some  in  whom 
the  skin,  in  front  of  the  elbow  and  behind  the  wrist, 
was  loose,  and  stretched  across  the  joint  a  little  like 
the  wing  of  a  bat.  This  reptile,  climbing  into  the 
trees  to  escape  its  enemies,  found  that  this  loose  llap 
of  skin  served  it  nicely,  and  sailed  out  of  the  trees 


l82  THE    MEANING    OF    EVOLUTION 

in  a  manner  not  unlike  that  of  the  flying  squirrel  of 
to-day.  Among  these  experimenters  in  aviation,  cer- 
tain forms  produced  scales  which  became  elongated 
and  finally  slit  up  along  the  side.  These  slit  scales 
slowly  developed  into  the  feathers  of  the  birds  of 
to-day.  Whether  the  steps  by  which  the  change  oc- 
curred have  been  correctly  stated  or  not,  the  result 
is  sure.  In  the  rocks  of  the  chalk  period  we  find  the 
remains  of  an  interesting  creature.  If  nothing  but  its 
bones  had  been  found  it  would  have  been  called  a 
reptile.  It  had  a  long  tail,  it  had  claws  on  its  front 
limbs ;  it  had  teeth  in  its  mouth ;  it  had  a  flexible 
backbone.  All  of  these  are  reptilian  rather  than  bird 
characters.  Yet  on  the  rocks  surrounding  these  bones 
are  the  unmistakable  impressions  of  the  feathers  of 
the  wings  and  of  the  tail.  Nothing  in  the  world  to- 
day has  feathers  excepting  the  birds,  and  in  this  ''an- 
cient winged  thing,"  for  this  is  the  significance  of  its 
name — archccopteryx — we  have  perhaps  the  most  re- 
markable link  in  the  world  between  two  distinct  sec- 
tions of  the  animal  kingdom.  Here  is  a  creature  half 
reptile,  half  bird;  perhaps  one-third  reptile  and  two- 
thirds  bird.  It  was  about  the  size  of  the  crow.  A 
little  later  unmistakable  bird  skeletons  will  appear,  but 
still  their  jaws  are  provided  with  long  conical  teeth. 
Still  more  interesting  from  our  standpoint  is  an- 
other set  of  primitive  animals,  utterly  insignificant  in 


' 


J* 


LIFE   IN    THE    PAST  183 

appearance,  but  of  momentous  importance  on  account 
of  their  later  history.  Among  these  reptiles  were  a 
few  small  creatures  perhaps  not  much  bigger  than 
mice  or  moles.  Their  teeth  were  a  little  more  com- 
plicated and  specialized  than  the  teeth  of  their  rep- 
tilian cousins.  Between  their  scales  were  small  and 
sparse  hairs.  Almost  nothing  but  their  jaws  remain 
to-day  to  tell  us  anything  about  them.  But  in  this 
humble  little  creature  of  the  Mesozoic,  utterly  insig- 
nificant beside  the  tremendous  reptiles  of  the  time,  we 
discern  the  ancestor  of  the  mammals.  These  were 
the  progenitors  of  the  horses  and  cows,  of  the  cats 
and  dogs,  of  the  monkeys  and  apes,  of  the  men  of 
to-day. 

During  this  chalk  period,  which  forms  the  last  por- 
tion of  the  age  of  reptiles,  life  for  the  first  time  grew 
to  look  much  as  it  does  to-day.  Now,  apparently,  the 
cold  of  winter  and  the  heat  of  summer  followed  each 
other  in  regular  succession.  There  have  been  colder 
and  warmer  periods  at  various  times  in  the  previous 
history  of  the  earth,  but  undoubtedly  they  were  more 
uniformly  cold  or  uniformly  warm  than  now.  Ages 
were  warm,  or  ages  were  cold,  but  now  the  earth 
clearly  shows  the  annual  alternations  of  summer  and 
winter,  and  for  the  first  time  clearly  shows  the  bands 
of  climate  on  the  earth  which  we  know  as  zones. 

In  the  chalk  period  this  new  factor  of  cold  works 


184  THE    MEANING    OF    EVOLUTION 

mightily  in  favor  of  the  mammals.  Their  reptilian 
ancestors  were  cold  hlooded.  When  the  climate  was 
warm  they  were  active;  when  the  climate  was  cold 
they  were  sluggish.  With  the  continuation  of  the 
annual  alternations  of  cold  and  warm  weather  that 
had  now  set  in  upon  the  earth,  the  little  birds  and 
mammals  had  in  their  warm  blood  an  advantage 
which,  in  the  long  run,  enables  them  not  simply  to 
compete  with  their  reptile  forefathers,  but  to  outdis- 
tance them  absolutely  in  the  race.  Here  and  there, 
on  earth  to-day,  exist  a  few  big  reptiles  like  the  croco- 
diles and  the  boa  constrictors.  But  they  are  few  and 
comparatively  insignificant  among  the  multitudinous 
population  of  the  globe  and  are  confined  to  the  hotter 
portions  of  the  earth.  For  the  most  part,  the  reptiles 
now  play  an  insignificant  and  unobtrusive  part.  The 
little  molelike  creatures,  practically  unnoticed  between 
their  feet  in  the  later  Mesozoic,  have  come  to  supplant 
them  entirely,  and  almost  to  rival  them  in  size.  While 
the  reptiles  have  grown  steadily  smaller,  the  mam- 
mals have  steadily  become  larger. 

While  there  is  no  land  mammal  to-day  as  big  as 
the  heaviest  of  the  reptiles  in  the  Mesozoic,  the  whale, 
which  is  one  of  the  mammals  that  has  again  taken  to 
the  ocean,  surpasses  in  size  even  those  gigantic  crea- 
tures. There  never  lived  in  the  world  before  a 
creature  quite  so  big  as  the  biggest  of  our  whales. 


LIFE  IN    THE   PAST  1 85 

Size,  however,  is  not  the  most  important  point  in  any- 
animal.  Speed,  sagacity,  variabiHty,  and  power  of 
adaptation,  these  are  the  quahties  which  the  world 
prizes,  and  these  the  new  mammals  possessed. 

The  next  geological  era  is  the  Cenozoic,  or  period 
of  modern  life.  This  is  divided  into  two  quite  dis- 
tinct sections,  the  Tertiary  and  the  Quaternary.  This 
era  began  about  five  million  years  ago,  roughly  speak- 
ing, and  is  still  going  on.  The  greater  half  of  it  is 
known  as  the  Tertiary.  It  was  during  this  time  that 
the  mammals  came  to  their  own.  At  first  these  crea- 
tures belonged  to  what  the  scientist  knows  as  gener- 
alized types.  They  are  jacks-of-all-trades.  The  stu- 
dent of  early  animal  life  finds  in  the  little  Phenacodus, 
which  was  scarcely  bigger  than  a  good-sized  setter 
dog,  the  beginnings  from  which  many  forms  have 
subsequently  developed.  This  creature  showed  points 
of  structure  which  to-day  may  be  seen  in  such  diversi- 
fied animals  as  the  dog,  the  horse,  the  rabbit,  and  the 
monkey.  It  is  not,  of  course,  suggested  that  Phe- 
nacodus was  the  immediate  ancestor  of  any  of  these. 
But  there  were  no  animals  in  those  times  more  like 
these  I  have  mentioned  than  was  Phenacodus,  and 
from  forms  like  it  in  main  features  all  of  these  other 
animals  have  since  been  derived,  each  species  of  ani- 
mal having  become  adapted  to  one  particular  kind  of 
life.    The  development  of  diversified  situations  on  the 


1 86  THE    MEANING    OF    EVOLUTION 

earth,  the  varieties  of  cHmate,  the  variation  between 
marsh  and  upland,  between  valley  and  plateau,  furnish 
a  complexity  of  environment  into  each  niche  of  which 
a  new  form  of  animal  fitted  itself. 

^^'ith  the  increased  complexity  of  mammals  comes 
the  submergence  of  the  reptiles  and  amphibians  to- 
day. In  all  sorts  of  situations  we  find  mammals.  The 
old-fashioned  continent  of  Australia  is  separated  from 
everything"  about  it  by  deep  water,  impassable  to  any 
animal  which  lives  upon  it.  In  this  secluded  country 
evolution  is  very  slow  and  animals  are  very  anti- 
quated. We  still  find  there  mammals  with  the  ancient 
habit  of  laying  eggs  in  a  hollow  in  the  ground,  though 
after  these  eggs  are  hatched  the  young  are  nursed  on 
the  milk  of  the  mother.  But  on  the  great  continental 
stretches,  where  competition  is  keen,  where  the  animal 
must  battle  for  his  life  against  a  wide  field  of  other 
animals,  where  migration  into  new  situations  is  pos- 
sible, the  rapidity  of  the  development  has  been  very 
much  greater. 

It  is  in  such  a  situation  that  man  has  arisen.  In 
the  extreme  southeastern  portion  of  Asia,  and  on  the 
islands  lying  close  to  the  coast,  his  highest  non-human 
relatives,  members  of  the  ape  family,  have  reached 
their  best  development.  These,  of  course,  are  not 
man's  ancestors.  They  are  the  less  progressive  mem- 
bers   who    are    left    behind    entirely    in    the    race. 


LIFE   IN    THE   PAST  187 

Whether  we  have  to-day  any  traces  of  the  steps  by 
which  man  arose  from  the  animal  beneath  him  is 
vigorously  disputed.  Eminent  scientists  will  be  found 
on  both  sides  of  this  question. 

Many  scientific  writers  to-day  take  it  for  granted 
that  one  form,  discovered  in  Java,  while  it  may  not 
be  in  the  absolutely  direct  line,  must  be  very  close 
indeed  to  the  line  of  ascent  toward  man  out  of  the 
apelike  forms.  A  scientist  by  the  name  of  DuBois, 
working  in  the  banks  of  a  stream  in  south-central 
Java,  found  a  thigh  bone  which  seemed  to  him  ex- 
ceedingly human  in  its  general  character  and  yet  not 
absolutely  like  the  human  thigh  bone.  The  oncom- 
ing of  the  rainy  season  raised  the  water  in  the  river 
so  that  DuBois  could  not  continue  his  search.  Re- 
turning a  year  later,  and  digging  back  deeper  into 
this  bank,  he  found  a  skull  cap  and  two  molar  teeth 
which  seemed  to  him  to  belong  to  the  thigh  bone,  al- 
though they  lay  several  yards  farther  back,  but  at 
the  same  level  in  the  bank. 

When  these  bones  were  subsequently  presented  to  a 
meeting  of  European  scientists  by  DuBois,  he  claimed 
to  have  found  the  "missing  link"  for  which  there  was 
so  eager  a  demand.  Some  of  the  best  anatomists  of 
the  meeting,  notably  Virchow,  laughed  at  his  claim 
and  said  that  the  skull  cap  was  simply  that  of  a  hu- 
man idiot,  and  could  be  duplicated  in  any  large  asylum. 


l88  THE   MEANING   OF   EVOLUTION 

A  committee  of  twelve  naturalists  was  appointed  to 
report  upon  Dubois'  find.  Of  this  committee  three 
asserted  the  bones  to  be  those  of  a  low-grade  man, 
three  insisted  that  they  belonged  to  a  high  ape,  of  a 
type  somewhat  higher  than  any  we  know  to-day,  but 
still  distinctly  an  ape.  Six  members  of  the  commit- 
tee of  twelve  agreed  that  the  remains  were  those  of  a 
creature  higher  than  an  ape  and  lower  than  any  nor- 
mal man,  and  represented,  in  their  opinion,  a  stage 
distinctly  along  the  line  of  development  out  of  the 
apes  and  into  man. 

This  so-called  ''Java  find"  is  known  in  science  by 
the  name  of  Pithecanthropus,  which  means  the  ape- 
man.  Whether  we  look  upon  this  fossil  as  a  serious 
find  or  not,  it  is  very  certain  that  in  the  caves  of 
Europe  belonging  to  the  Quaternary  period  we  find 
abundant  evidences  of  primitive  man.  The  older  these 
evidences  are,  the  more  likely  they  are  to  be  dis- 
tinctly below  the  grade  of  man  of  to-day,  in  the  size 
and  shape  of  the  brain  case  and  in  the  length  and 
massiveness  of  the  jaw. 

There  are  probably  more  races  than  one  repre- 
sented among  these  skulls.  Some  of  them  are  surely 
well-deserving  of  the  title  of  low  brow.  Their  heavy 
ridges  over  the  eyes,  their  small  foreheads,  their  mas- 
sive, heavy-set  jaws  show  a  race  of  men  far  less  en- 
dowed  mentally   and   much   better    endowed    in   the 


LIFE   IN    THE    PAST  1 89 

matter  of  brute  force  than  the  men  of  to-day.  These 
skeletons,  or  parts  of  skeletons,  are  turning  up 
every  year,  and  we  are  just  beginning  to  know  much 
about  them.  Capable  men  are  studying  them  with 
much  care.  The  next  fifty  years  may  not  improbably 
make  the  history  of  the  ascent  of  man  as  clear  as  is 
now  that  of  the  horse,  to  which  we  shall  refer  later. 
The  whole  question  of  the  descent  of  man  from  the 
lower  animals,  or  his  ascent  from  them,  as  Drummond 
aptly  termed  it,  is  to  most  people  so  entirely  repug- 
nant as  to  set  them  at  once,  and  finally,  against  all 
willingness  to  consider  the  question  of  Evolution. 
This,  however,  does  not  solve  the  problem.  Even 
though  truth  be  horribly  unpalatable,  it  is  still  to  be 
believed  if  it  is  only  the  truth.  There  is  practically 
no  doubt  left  among  scientific  men  of  the  origin  of 
man  in  lower  forms.  The  evidences  grow  more  and 
more  complete  year  by  year,  and  from  every  line  of 
investigation.  Whether  we  study  his  anatomy,  his 
embryology,  his  history,  his  language,  or  his  civiliza- 
tion, all  indications  point  in  the  same  direction.  Con- 
stant discoveries  indicate  the  fact  of  an  enormously 
long  development  from  a  very  humble  form.  If  this 
proves  to  be  true  and  remains  unpalatable,  the  fault 
lies  in  the  palate  and  not  in  the  truth.  Gradually  we 
are  coming  to  understand  that  there  is  no  reason  why 
this  truth  should  be  unpalatable.     We  consider  a  rise 


190  THE    MEANING    OF    EVOLUTION 

from  humble  conditions  to  be  the  glory  of  our  heroes; 
we  esteem  it  an  added  charm  in  their  strength  that 
they  should  have  developed  from  untoward  surround- 
ings. It  is  not  a  disgrace  to  man  to  have  descended 
from  the  apes.  It  is  to  the  glory  of  man  that  he 
should  have  ascended  from  forms  not  much  more 
promising-looking  than  the  apes  of  to-day.  We  must 
repeat,  however,  that  the  apes  were  the  unprogressive 
members,  and  hence  we  must  not  judge  man's  ances- 
tors too  harshly.  It  must  have  been  in  them  to  rise. 
But  the  great  glory  in  the  thought  of  the  humble 
ancestry  lies  in  the  possibilities  of  his  future.  If  out 
of  a  creature  not  materially  unlike  the  gibbering  ape 
of  to-day  there  should  have  come,  under  the  guiding 
hand  of  an  Almighty  God,  creatures  with  the  endow- 
ments and  capabilities  of  man  of  to-day,  then  this  is 
only  an  earnest  and  foretaste  of  that  which  may  be 
expected  in  the  future.  A  time  will  come  when  man 
shall  have  risen  to  heights  as  far  above  anything  he 
now  is  as  to-day  he  stands  above  the  ape.  Even 
then  there  seems  no  end.  With  Infinite  Power  as  the 
agent,  and  limitless  time  in  which  to  work,  man  would 
be  limiting  God  to  an  extent  unwarranted  by  the  his- 
tory of  the  past  to  imagine  that  His  process  had 
stopped  to-day,  and  that  man,  with  his  many  imper- 
fections of  body,  of  mind,  and  of  morals,  should  be 
the  best  that  is  yet  to  come.     There  cling  to  him  still 


LIFE   IN    THE    PAST  I9I 

the  limitations  and  dregs  of  his  brute  Hfe.  Often  the 
brute  in  him  comes  to  the  surface.  Little  by  little 
he  is  coming  to  be  dominated  by  the  qualities  God  has 
last  given  him.  Slowly  the  brute  shall  sink  away, 
slowly  the  divine  in  him  shall  advance,  until  such 
heights  are  attained  as  we  to-day  can  scarcely  im- 
agine. As  we  can  scarcely  conceive  the  beginnings 
of  this  process,  so  we  can  with  difficulty  imagine  its 
end.  This  only  can  be  seen  by  the  Eternal  through 
whom  it  shall  all  come  to  pass,  and  by  whom  all  will 
in  time  be  accomplished. 


CHAPTER    VII 

How  THE  Mammals  Developed 

When  the  idea  of  evolution  first  began  to  be  much 
discussed,  especially  after  the  publication  of  the  "Ori- 
gin of  Species,"  there  were  several  points  which  ap- 
peared to  be  more  than  commonly  difficult  of  ex- 
planation. It  did  not  seem  impossible  that  the  vari- 
ous types  of  domesticated  cattle  should  have  descended 
from  a  common  ancestor.  It  did  not  seem  difficult 
of  comprehension  that  the  dog  might  once  have  been 
a  wolf.  Though  not  quite  so  credible,  it  did  not  seem 
absurd  that  the  tigers,  lions,  and  leopards  should  have 
once  all  been  alike.  The  resemblance  between  these 
are  strong  enough  to  make  ti.e  idea  seem  conceivable. 
Though  men  were  willing  to  concede  this  much,  they 
insisted  that  the  great  branches  of  the  animal  king- 
dom varied  so  widely  from  each  other  as  to  make  it 
certain  that  each  was  a  separate  creation.  It  was  par- 
ticularly objected  that  the  mammals  differed  so  en- 
tirely from  other  animals  in  several  important  par- 
ticulars that  a  special  divine  act  was  necessary   for 

their  appearance.     The  mammals  have  a  furry  cover- 

192 


HOW    THE   MAMMALS    DEVELOPED  I93 

ing  entirely  different  from  the  clothing  of  any  other 
animal  in  the  kingdom,  and  have  warm  blood,  which 
is  found  nowhere  else  except  among  the  birds.  But 
particularly  their  method  of  producing  their  young 
seemed  so  entirely  different  from  that  of  any  other 
group  that  here  a  special  creation  was  deemed  abso- 
lutely necessary. 

Other  young  creatures  are  produced  from  eggs  laid 
by  the  parent  and  subsequently  hatched.  The  young 
of  the  mammals  are  born  alive  and  comparatively 
well  developed.  In  addition,  their  first  food,  the  milk 
of  the  mother,  is  so  entirely  different  from  the  food 
of  any  other  creature  that  this  again  seemed  to  in- 
volve a  separate  creation.  Gradually  we  have  come  to 
understand  the  whole  matter  of  reproduction  very 
much  better.  Minute  and  careful  dissections  of  rab- 
bits, of  dogs  and  cats,  of  animals  slaughtered  for  food, 
with  occasional  post-mortem  examinations  of  human 
beings  in  various  stages  of  the  development  of  the 
young,  leave  us  no  longer  in  doubt  concerning  the 
main  features  of  the  process.  The  better  we  come 
to  understand  it  the  more  clearly  it  becomes  evident  .1'' 
that  in  the  development  of  the  mammals  we  have  no 
new  procedure,  but,  as  in  so  many  other  activities, 
new  developments  of  an  old  process. 

There  are  two  entirely  different  methods  by  which 
new  animals  and  plants  may  arise.     One  sees  some- 


194 


THE    MEANING   OF    EVOLUTION 


times  in  the  home  of  a  friend  a  geranium  of  par- 
ticular beauty,  the  hke  of  which  he  would  be  glad  to 
possess.  The  accommodating  friend  cuts  a  small  piece 
from  the  geranium.  This  is  stuck  into  poor  but  well- 
watered  ground,  develops  roots,  and  eventually  grows 
into  a  geranium  stalk  exactly  like  the  one  from  which 
it  came  and  of  which  it  is  in  reality  only  a  detached 
part. 

In  similar  fashion,  if  one  wants  a  particular  kind 
of  apple,  he  never  trusts  to  planting  an  apple  seed. 
Going  to  the  tree  of  the  variety  he  desires,  he  takes 
from  it  a  small  twig  provided  with  a  bud  and  inserts 
this  bud  into  a  cleft  made  in  the  young  branch  of 
another  apple  tree.  The  young  bud  so  inserted  starts 
up  into  a  new  branch,  resembling  almost  absolutely, 
not  the  tree  wdiich  feeds  it  with  sap,  but  the  tree  from 
which  the  bud  was  originally  taken. 

When  we  w^ish  a  particular  variety  of  potato  we 
obtain  pieces  of  the  potato  of  the  kind  we  desire. 
Each  of  these  must  contain  an  eye,  which  is  a  bud 
of  the  old  potato.  When  the  sprout  appears  the  new 
plant  will  be  practically  identical  in  character  with 
the  plant  from  which  the  potato  was  taken.  This  sort 
of  reproduction,  in  which  a  piece  of  the  old  parent 
grows  up  into  the  new  generation,  is  called  the  asexual 
method.     But  one  parent  is  concerned  in  the  process, 


HOW    THE    MAMMALS    DEVELOPED  I95 

and  the  offspring  are  as  nearly  as  may  be  like  the 
parent  from  which  they  arose. 

The  gardener  who  wishes  to  obtain  new  varieties 
is  not  content  with  this  method.     If  he  plant  the  seed 
of  the  potato  the  outcome  will  be  most  uncertain.    His 
seed  must  be  taken,  of  course,  from  the  fruit  of  the 
potato,  and  most  of  these  plants  never  fruit.     Every 
grower  of  large  quantities  of  potatoes  will  have  no- 
ticed occasionally,  on  the  tops  of  the  plant,  after  the 
flowers  disappear,  a  globular  growth  looking  not  un- 
like a  small  tomato,  but  with  a  tendency  to  become 
purplish  green   in  color.     This   is  the   fruit  of  the 
potato  and  in  it  are  the  seeds.   When  these  are  planted 
all  sorts  of  potatoes  are  liable  to  start  up.     Most  of 
them  will  prove  worthless.     An  occasional  seed  may 
produce  an  uncommonly  fine  plant.     This  new  variety 
may  thereafter  be  propagated  from  the  tuber,  as  the 
potato  itself  is  called,  and  the  new  strain  will  be  kept 
constant  in  this  way.     This  method  of  using  the  seed 
for  reproducing  the  plant  is  called  the  sexual  method, 
because  two  parents  cooperate  in  the  production  of 
the  seed.     The  pollen  came  from  one  parent  and  the 
ovule,   which  after   fertilization  swelled  up  into  the 
seed,   came   from  another.     By  this  combination  of 
two  individuals  new  varieties  become  quite  possible. 
Nature  seems  to  be  more  concerned  in  improving  her 
strain  than  in  maintaining  her  older  strains.     In  all 


196  THE    WEANING    OF    EVOLUTION 

uf  her  lowest  plants  and  animals  she  uses  the  asexual 
method  of  reproduction.  As  we  go  higher  in  the  or- 
ganic world  the  two-parent  method  becomes  increas- 
ingly common.  When  we  reach  the  higher  animals, 
and  most  of  the  higher  plants,  this  plan  of  double 
parenthood,  the  sexual  method,  alone  is  used. 

In  order  that  we  may  the  more  clearly  understand 
how  the  mammals  produce  their  young  and  nourish 
them,  we  shall  begin  at  the  lowest  class  of  the  back- 
boned animals  and  note  how  the  process  is  there  ac- 
complished. As  we  pass  upward  through  the  king- 
dom the  method  acquires  greater  complexity.  When 
we  finally  reach  the  mammals,  what  at  first  seemed  an 
absolutely  new  process  will  prove  to  be,  as  is  all  of 
nature's  work  with  which  we  are  thoroughly  ac- 
quainted, but  a  modification  and  an  elaboration  of 
some  previously  existing  process. 

Some  time  ago  I  was  passing  the  early  months  of 
summer  by  the  side  of  a  lake  in  northern  Pennsyl- 
vania. Near  my  tent,  on  the  edge  of  the  water,  was 
a  wharf  from  which  it  was  possible  to  look  dowai  into 
the  shallows  about  the  edge  of  the  lake.  In  early 
July  the  bottom  began  to  take  on  a  strange  appear- 
ance. Spots  as  big  as  a  dinner  plate  became  evident 
because  they  were  cleaned  of  the  finer  sand  or  mud 
which  is  common  on  the  bottom.  A  close  examina- 
tion showed   that  each   of   these   circular   spots  was 


HOW    THE   MAMMALS   DEVELOPED  I97 

being  occupied  and  cleaned   up  by   a  sunfish.     The 
pebbles  were  lifted  into  the  mouth  of  the  fish  and 
driven    out    again    with    force.      The    water    which 
emerged  with  the  stones  seemed  to  wash  away  the 
dirt,  while  the  pebbles  themselves  became  gradually 
cleaned  of  the  green  plant  life  which  ordinarily  covers 
them.    After  the  process  was  completed  each  spot  was 
saucer-shaped  and  free  from  scum  and  mud.     Over 
each  of  these  spots  hovered  the  sunfish  which  made 
it,  and  round  and  round  the  fish  swam.     The  circles 
thus  traversed  were  so  near  each  other  that  every 
now  and  then  the  occupants  of  two  adjoining  nests 
would  meet  on  the  border.    The  fish  which  was  most 
nearly  on  its  own  ground  would  at  once  attack  the 
other  and  drive  him  away.     In  a  few  days  the  other 
partner  in  each  family  seemed  to  appear.     Now  two 
fishes  swam  side  by  side  over  each  nest,  bringing  the 
lower  edge  of  their  bodies  comparatively  close  to- 
gether.    In  this  position  they  moved  around  over  the 
pebbly  bottom.    The  female  was  discharging  her  mul- 
titudinous and  very  small  eggs,  so  that  they  dropped 
to  the  bottom  of  the  nest.     At  the  same  time  the  male 
was  expelling  what  in  fish  is  known  as  the  milt.     In 
this  milt  are  the  sperm  cells  of  the  male,  each  consist- 
ing of  a  rounded  head  and  a  very  slender  body.   These 
are  attracted  by  the  eggs.     Pushing  up  against  them, 
the  head  of  a  sperm  cell,  consisting  almost  entirely 


KjS  THE    MEANING    OF    EVOLUTION 

of  the  nucleus  of  the  cell  and  carrying  the  determi- 
nants which  were  to  decide  one-half  of  its  future  char- 
acters, penetrated  this  egg  and  fused  with  its  nucleus. 
This  was  filled  with  the  determinants  of  the  charac- 
ters inherited  from  the  mother.     Of  course  many  of 
the  eggs,  of   which  probably  there  are   a  thousand, 
must  have  escaped  fertilization.     There  are  doubtless 
a  thousand  sperm  cells  that  went  to  utter  waste  for 
one   which    found   an   egg  to    fertilize.      These   eggs 
nestled  in  the  crevices  between  the  stones  in  the  w^arm 
water  of  the  edge  of  the  lake.     Here  the  sun  could 
easily  penetrate  to  the  bottom  and  hatch  them.     The 
little  fish,  still  guarded  by  one  hovering  parent,  swam 
around  in  the  water  long  before  the  yolk  of  the  egg, 
containing  its   large  amount  of    food,    had  been  ab- 
sorbed into  the  tissues  of  the  young  fish.     This  fatty 
store  made  the  abdomen  of  the  fish  in  which  it  lay 
protrude  enormously.     Gradually  the  fish  grew  larger 
and  the  yolk  grew  smaller  until  all  had  been  consumed. 
Soon  the  fish  began  to   forage   for  himself  and  no 
longer  to  demand  or  care  for  the  company  and  pro- 
tection   of   its   parent.      The   little    sunfish    is    highly 
favored  among  his  comrades  in  having  any  care  w^hat- 
ever  by  the  parent.     In  the  case  of  most  fishes  the 
female,  swimming  slowly  over  the  bottom,  deposits 
her  eggs,    which   are    fertilized   by   the   male,    which 
follows  behind  her.     After  the  eggs  have  thus  been 


HOW    THE    MAMMALS    DEVELOPED  IQQ 

laid  and  quickened  no  other  attention  is  paid  to  them 
by  either  of  the  parents. 

Fish  are  stupid  ahiiost  beyond  the  comprehension 
of  those  who  are  not  students  of  the  minds  of  ani- 
mals. Frogs  and  toads  are  a  distinct  step  in  advance, 
and  hence  their  mental  activities  play  a  larger  part  in 
the  process. 

In  the  love-making  of  the  frogs  and  toads  the  song 
has  an  important  share.  In  each  species  the  voice  is 
a  little  different  from  that  of  any  other.  In  our 
familiar  garden  toad  we  have  an  excellent  illustra- 
tion of  the  method  common  to  the  entire  group. 
When  spring  comes  an  impulse  seems  to  stir  in  all 
the  toads  of  a  neighborhood.  Heretofore  they  have 
stuck  faithfully  to  dry  ground;  now  they  start  off  for 
the  water.  Whether  their  impulse  is  simply  to  move 
down  hill  or  whether  they  by  some  means  detect  the 
near  presence  of  water,  I  cannot  say.  Certainly  a 
new  fountain  on  a  lawn  will  secure  in  spring  its 
prompt  and  full  share  of  the  neighborhood's  toads. 
In  any  event  the  toads  of  a  district  congregate  in 
great  numbers  in  any  pond  or  along  the  edge  of  any 
moderate  stream.  Within  a  short  time  their  llutelike, 
quivering  voice  is  heard  far  and  wide.  That  this  note 
has  an  attractive  power  over  the  female  there  is  no 
doubt.  She  herself  makes  no  effort  to  imitate,  but 
the  song  of  her  mate  is  persistent  and  exceedingly 


200  THE    MEANING    OF    EVOLUTION 

sweet.  I  have  seen  a  male  sit  upon  a  clump  of  grass 
and  utter  his  love  call.  Uefore  he  had  been  singing- 
for  more  than  half  a  minute  three  females  hastened 
toward  him  from  a  distance  of  perhaps  twenty  feet. 
Each  seemed  anxious  to  reach  as  promptly  as  pos- 
sible the  creature  whose  voice  had  proved  so  attrac- 
tive. When  the  mating  comes,  the  female  discharges 
a  series  of  small  shotlike  eggs  which  are  encased  in 
a  very  tenacious  mucous.  While  they  are  being  de- 
posited the  male  fertilizes  them.  No  sooner  have  the 
eggs,  fertilized  by  the  sperm  cells,  reached  the  water 
than  the  mucous  at  once  begins  to  swell.  The  result 
is  that  eggs  appear  encased  in  two  slender  strings  of 
jelly,  each  having  a  diameter  about  that  of  a  lead 
pencil.  At  intervals  of  not  more  than  half  an  inch 
the  shotlike  eggs  may  be  seen.  The  mother  toad,  in 
laying  these  eggs,  moves  about  rather  restlessly  in 
the  water.  By  this  means  she  succeeds  in  wrapping 
the  strings  about  the  grass  and  sticks  of  the  pool. 
This  will  hold  them  quite  safely  even  against  a  con- 
siderable current  of  water,  should  the  stream  rise  and 
Hood  the  side  pools  in  which  the  eggs  are  laid.  With 
this  amount  of  care,  however,  the  attention  of  both 
parents  to  the  young  entirely  ceases.  They  are  now 
abandoned  to  the  chances  of  a  fortune  to  them  ex- 
ceedingly unkind.  A  toad  will  lay  about  five  hundred 
eggs.     It  is  evident  that  on  the  average  only  two  of 


HOW    THE    MAMMALS    DEVELOPED  20I 

these  can  attain  maturity  by  the  time  the  parents  have 
died,  for  the  number  of  toads  does  not  materially 
alter  season  by  season.  The  connecting  string  is  made 
up  not  of  nourishment  for  the  eggs,  but  of  a  bitter 
mucous  so  unpleasant  to  the  taste  that  fish  are  thus 
deterred  from  eating  the  otherwise  nourishing  ma- 
terial. This  secures  for  the  young  embryo  a  chance 
to  mature  which  in  the  absence  of  the  jelly  it  would 
entirely  lack.  Imbedded  in  this  mucous  is  the  embryo 
itself,  surrounded  by  a  small  amount  of  albumen  and 
containing  inside  of  itself  a  very  considerable  amount 
of  yolk.  This  gives  to  the  egg  a  volume  possibly  a 
hundred  times  that  of  the  egg  of  the  sunfish.  Thus, 
even  counting  the  care  the  parent  sunfish  took  of  its 
offspring,  which  care  is  very  uncommon  among  fishes, 
the  toad  stands  a  distinctly  better  chance  in  life.  The 
protection  of  the  bitter  mucous  and  the  large  amount 
of  yolk  permitting  considerably  larger  development 
before  leaving  the  Qgg,  give  to  the  toad  a  ma- 
terial  advantage.  When  the  toad  first  emerges  from 
the  Qgg  it  is  amazingly  like  the  fish.  It  has  gills  at 
the  side  of  its  neck  and  swims  by  the  movement  of 
its  tail.  Later  its  limbs  develop,  the  hind  ones  coming 
first,  its  tail  is  absorbed,  and  it  is  now  a  true  toad, 
ready  to  leave  the  water. 

Altogether  a  higher  state   of   reproduction  is  en- 
countered when  we  reach  the  reptiles,  which  are  the 


202  THE    MEANING    OF    EVOLUTION 

next  liic;hcr  class  of  backboned  animals.  Here  very 
distinct  developments  of  the  process  are  discovered. 
The  turtle,  to  use  the  best  known  illustration,  may 
lay  but  twenty  eggs.  But  she  will  not  lay  them  at 
random  in  the  water,  as  do  the  toads  and  the  fish. 
Each  egg  is  wonderfully  fattened  with  yolk.  This 
means  that  it  is  possible  for  the  creature  to  develop 
to  a  far  greater  extent  before  leaving  the  egg  than 
w^as  possible  in  the  case  of  the  toad.  Accordingly 
the  little  turtle,  while  it  begins  life  not  unlike  a  fish 
and  goes  through  the  gilled  and  tailed  period,  during 
which  it  is  not  luilike  a  tadpole,  passes  beyond  this 
period  before  leaving  the  shell  and  has  already  ac- 
quired its  full  turtle  characters  when  first  it  steps  upon 
the  scene.  So  big  an  egg  as  this  would  be  highly 
nutritious  and  animals  would  desire  it  immensely  for 
food.  Hence  it  becomes  necessary  for  the  turtle  to 
securely  hide  her  eggs.  In  order  to  do  this,  she 
scoops  out  a  pit  in  the  sand  in  which  she  deposits 
them  and  here  they  develop.  If  no  further  provi- 
sions were  made  the  eggs  of  the  toad  would  dry  com- 
pletely and  never  hatch.  Accordingly  it  becomes 
necessary  for  the  turtle  to  enclose  each  egg  in  a  tough, 
leathery  membrane,  known  as  the  shell.  Because  the 
egg  is  thus  encased  it  is  necessary  for  it  to  be  fertil- 
ized before  lacing  laid.  Accordingly  the  male  must 
place  the  sperm  cells  within  the  body  of  the  female. 


is 


HOW    THE    MAMMALS    DEVELOPED  203 

These  cells  swim  nearly  to  the  top  o£  the  tubes  in 
which  they  are  placed,  and  there  fertilize  the  descend- 
ing eggs.  Farther  down  the  canal  the  shell  is  se- 
creted about  the  now  swollen  mass  of  yolk  and  white, 
comjDleting  the  tgg  just  before  it  leaves  the  parent. 

If  the  evolutionist  understands  properly  the  line  of 
descent,  the  birds  and  mammals  are  both  the  descend- 
ants of  the  reptiles.  While  there  is  less  exterior  re- 
semblance between  a  chicken  and  a  turtle  than  be- 
tween a  cat  and  a  turtle,  the  real  relationship  in  the 
first  case  is  much  closer  than  in  the  second.  This  is 
perhaps  most  easily  seen  in  the  scaley  legs  of  both 
bird  and  reptile.  Another  remarkable  resemblance 
lies  in  the  fact  that  in  both  cases  the  eggs  are  large, 
well  stored  with  nourishment,  and  protected  by  a  re- 
sistant  shell. 

So  few  people  know  the  turtle's  egg  that  it  will  be 
better  to  describe  that  of  the  hen,  which  it  largely 
resembles.  Underneath  the  hard  shell  is  a  tough  but 
flexible  membrane  which  lies  against  the  limey  coat- 
ing, except  at  the  blunt  end,  where  a  separation  be- 
tween the  two  gives  room  for  a  bubble  of  air.  In- 
side of  this  shell  and  its  membrane  lies  the  white  of 
the  egg,  which  is  nourishment  for  the  chick,  though 
not  nearly  so  rich  as  the  yolk.  This,  besides  the 
albumen  which  it  contains,  is  stored  with  large  quan- 


204  THE    MEANING   OF   EVOLUTION 

titles  of  fat.  It  will  be  remembered  that  upon  breaking 
a  hen's  egg*  and  dropping  it  into  a  bowl,  the  yolk 
holds  together  because  it  is  enclosed  in  a  delicate  sac. 
As  the  yolk  falls  into  the  bowl  there  floats  to  the 
top  of  it  a  lighter  yellow  spot  as  big  as  the  end  of  a 
lead  pencil.  This  is  all  of  the  egg  which  thus  far 
represents  the  chick  itself.  All  the  rest  is  nourish- 
ment. This  disk  already  consists  of  three  reasonably 
distinguishable  layers  of  cells,  which  grow  rapidly 
different  from  each  other.  They  spread  and  bend 
and  twist,  forming  the  young  chick  and  a  set  of  or- 
gans which  serve  for  its  protection  and  maintenance 
during  its  embryonic  life.  Within  a  few  days  these 
accessory  organs  will  have  formed  distinctly.  Within 
the  upper  half  of  the  yolk  w\\\  be  found  the  small 
developing  chick,  which  for  the  first  thirty-six  hours 
of  its  development  passes  through  a  stage  not  unlike 
the  fish,  or  the  earlier  steps  of  the  turtle.  Within 
a  few  days  it  becomes  clearly  evident  that  this  crea- 
ture is  to  be  a  bird,  though  it  is  much  longer  before 
it  is  clearly  a  chick. 

This  embryo  is  so  soft  that  it  is  almost  like  curd 
in  thickened  milk,  and  could  be  very  easily  destroyed 
were  it  not  for  a  protective  device  which  Nature  has 
employed.  It  seems  necessary  that  it  should  be  pro- 
tected with  the  utmost  care.  The  matter  will  be 
better  understood  if  we  recall  a  common  experience. 


HOW    THE    MAMMALS    DEVELOPED  2O5 

Almost  everyone  has  tried  to  dissolve  some  substance 
in  water  in  a  vial.  If  the  bottle  be  filled  with  fluid 
to  the  top  and  corked  it  is  very  difficult  to  shake  up 
the  contents.  Even  vigorous  agitation  produces  little 
movement  of  the  material  on  the  inside.  If  we  wish 
to  shake  up  the  solid  with  water  the  bottle  must  be 
left  partly  empty.  The  brain  of  a  human  being  is 
protected  by  just  the  same  device.  If  it  simply  lay 
within  the  skull  the  first  fall  would  mash  the  gray 
substance  against  the  side  of  the  cavity.  To  prevent 
this  calamity  the  bony  case  is  made  somewhat  larger 
in  capacity  than  the  brain  itself,  and  the  space  be- 
tween the  two  is  filled  with  a  watery  fluid.  This 
serves  to  prevent  jars  and  shocks.  In  the  hen's  egg 
the  same  plan  is  pursued.  The  embryo  lies  on  the 
inside  of  a  bag  considerably  larger  than  itself.  This 
sac,  called  the  amnion,  is  filled  with  a  watery  fluid. 
With  such  a  protection  only  the  most  severe  shock 
to  the  egg  would  sufficiently  jar  the  embryo  to  do  it 
any  harm.  The  ordinary  experiences  of  an  egg  leave 
it  undisturbed. 

Every  living  creature  requires  a  constant  supply  of 
food  and  of  oxygen.  The  embryo  is  a  living  crea- 
ture, and  is  no  exception  to  the  rule.  It  needs  an 
abundant  supply  of  easily  assimilated  food  and  of 
oxygen.  When  the  hen's  egg  is  first  laid  the  en- 
tire contents,  with  the  exception  of  the  little  light- 


206  THE    MEANING    OF    EVOLUTION 

colored  disk  which  iloats  on  the  top  of  the  yolk,  form 
the  nourishment.  The  disk  alone  is  the  living  organ- 
ism. In  the  earliest  stages  the  emljryo  receives  its 
food  by  simple  absorption  from  the  yolk.  As  the 
chick  increases  in  complexity  the  yolk  at  first  grows 
swampy,  with  fluid  trickling  here  and  there  through 
the  more  solid  portions.  Thin  walls  form  about  these 
little  streams,  thus  producing  blood  vessels  which 
cover  the  entire  surface  of  the  yolk.  These  absorb  the 
nourishment  and  turn  it  over  to  the  embryo.  As  the 
latter  grows  in  size  both  the  yolk  and  white  dimin- 
ish. The  embryo  soon  becomes  larger  than  the  remain- 
ing yolk  and  is  attached  to  it  by  a  cord  filled  with 
blood  vessels  which  enter  the  chick  near  the  center 
of  its  body.  The  abdominal  wall  has  an  opening  at 
this  point.  One  of  the  later  occurrences  in  the  life 
of  the  chick,  before  it  breaks  through  the  egg,  is  to 
have  the  last  remnant  of  the  yolk  and  its  sac  slip  to 
the  inside  of  the  abdomen,  which  then  completely 
closes  over  it. 

As  yet,  we  have  seen  no  arrangement  for  furnish- 
ing air  to  the  chick.  At  the  same  point  at  which  the 
blood  vessels  from  the  yolk  enter  the  chick,  another 
set  of  vessels  pass  in  and  out.  These  are  attached  to 
a  large  fiattened  bag  which  fioats  above  the  embryo 
against  the  upper  side  of  the  shell.  This  bag  is 
called  the  allantois,  and  serves  as  a  sort  of  lung  for 


HOW    THE    MAMMALS    DEVELOPED  20/ 

the  developing  chick.  The  shell  is  porous  enough  to 
allow  air  to  pass  through  it.  The  blood  vessels  of 
the  allantois  take  in  ox3^gen  and  give  out  carbon 
dioxide  through  the  porous  shell.  The  blood  thus 
altered  is  returned  to  the  chick  and  serves  its  life 
purposes.  One  of  the  reasons  why  the  chicken  must 
turn  its  eggs  in  the  nest  is  that,  if  the  allantois  re- 
main too  long  in  contact  with  the  upper  shell  of  the 
egg,  it  will  become  attached  to  it  and  will  not  there- 
after perform  its  functions. 

The  embryo  thus  enclosed  in  the  egg  finds  its  pro- 
tection in  the  fact  that  it  is  encased  in  a  fluid  con- 
tained in  the  amnion.  It  draws  its  nourishment  from 
the  yolk  upon  which  it  lives  and  the  nourishment  is 
transmitted  to  it  by  blood  vessels.  It  draws  its  oxy- 
gen and  throws  ofif  its  wastes  through  the  instru- 
mentality of  the  allantois,  which  covers  it  over.  Day 
by  day  the  chick  becomes  larger,  day  by  day  it  grows 
to  look  more  like  what  it  is  to  be.  By  the  nineteenth 
day  it  appears  to  be  complete.  Its  nervous  organiza- 
tion is,  however,  not  thoroughly  developed.  If  re- 
moved from  the  shell  the  chick  still  is  indisposed  to 
stand  upon  its  feet  or  to  run  about.  If  allowed  to 
remain  in  the  egg  until  the  twenty-first  day,  the  chick 
will  be  able  to  push  its  beak  through  the  skin  enclos- 
ing the  bubble  of  air  at  the  blunt  end  of  the  egg  and 
get  the  first  breath  into  its  lungs.     Now  it  gives  a 


208  THE    MEANING   OF    EVOLUTION 

faint  peep,  breaks  the  shell  of  the  egg,  and  steps  out 
into  the  open  air. 

I  have  given  this  somewhat  lengthened  description 
of  the  development  of  the  chick  because  of  the  light 
it  throws  upon  the  method  pursued  by  the  mammals. 
The  features  which  have  been  described  in  the  case 
of  the  chicken  s  egg  could  be  as   fully  observed  in 
the  case  of  the  turtle  or  any  of   the  other   reptiles. 
IMammals   are    descended    from    the    reptiles    of    the 
Mesozoic,   and   whatever   peculiarities   there   may  be 
in  their  method  of  producing  their  young  must  be 
derived  from  the  reptiles.     If  we  wish  to  know  how 
the  earliest  mammals  produced  their  young,  we  can 
only   judge  by  the   lowliest  members   of   the   group 
that  live  upon  the  earth  to-day.     The  most  primitive 
of  these  is  the  so-called  Duckmole,  of  Australia.   This 
little  creature  has  habits  not  unlike  those  of  the  musk- 
rat.     It  burrows  in  the  bank  of  a  stream,  and  makes 
a  nest  at  the  end  of  the  burrows  where  it  lays  its 
eggs.     This  is  one  of  the  very  few  warm-blooded,  hair- 
covered  animals  which  still  lays  eggs.     A  little  higher 
in  the   scale   stand   the   kangaroo   and   the   opossum. 
These  creatures  keep  the  egg  inside  of  the  body  until 
it  is  hatched.     But  this  happens  in  so  short  a  tim^ 
that  the  young  animal  is  exceedingly  immature  and 
as  yet  unable  to  stand  the  outside  air.     Accordingly 
there  is  a  double  fold  of  skin  on  the  abdomen  of  the 


HOW    THE    MAMMALS    DEVELOPED  209 

mother,  covering  her  breasts.  This  forms  a  suitable 
resting  place  into  which  these  young  are  conveyed  as 
soon  as  they  are  born  and  from  which  they  do  not 
emerge  for  many  days.  The  little  creature  instantly 
fastens  upon  the  nipple  of  the  mother,  keeping  its 
mouth  constantly  in  this  position.  At  intervals  the 
muscles  of  the  breast  force  the  milk  into  the  mouth 
of  the  young,  which  is  still  too  undeveloped  to  suck 
for  itself.  As  it  gets  older  the  little  opossum  or  kan- 
garoo emerges  from  the  pouch  in  the  pleasanter  part 
of  the  day  and  in  the  absence  of  danger.  It  returns 
to  the  mother's  pocket  as  soon  as  it  becomes  cold  or 
a  cry  from  its  parent  warns  it  of  its  defenseless  po- 
sition. 

These  creatures  are  the  lowliest  of  the  class  upon 
the  earth.  The  great  majority  of  all  mammals  have 
elaborated  a  far  finer  plan,  in  which  the  young  are 
retained  within  the  body  of  the  parent  until  they  are 
quite  able  to  stand  the  air.  The  length  of  this  time 
varies  in  different  mammals  from  a  few  weeks  to 
more  than  a  year.  The  egg  must  be  fertilized  before 
it  leaves  the  body  of  the  parent.  If  it  should  fail  in 
this  it  simply  passes  out  and  is  wasted.  If  the  fer- 
tilizing cell  reaches  the  egg  before  it  has  progressed 
far  down  the  tube  it  begins  its  development.  The 
embryo  forms  for  itself  the  sort  of  head  and  tail 
and  gill  slits  which  would  have  served  its  fish  or  its 


2IO  THE    MEANING    OF    EVOLUTION 

tadpole  ancestor.  Its  limbs  develop  as  little  buds  in- 
distinguishable from  similar  buds  that  would  have 
formed  fms  for  the  fish  or  wings  for  the  bird. 

Around  the  embryo  there  forms  a  sac,  the  amnion 
filled  with  a  lluid  which  serves  to  protect  the  young 
mammals  exactly  as  the  growing  chick  was  protected. 
Under  the  forming  creature  there  hangs  a  small  but 
empty  yolksac.  This  is  an  actual  remnant,  a  reminder 
of  the  past,  when  the  eggs  of  the  mammals  were  also 
packed  with  yolk  and  the  growing  embryo  secured 
its  nourishment  exactly  as  does  the  maturing  chick. 
But  a  new  method  has  been  provided  for  the  mam- 
mal, and  consequently  the  yolksac,  though  it  has  not 
entirely  disappeared,  has  no  nutritive  content  for  the 
growth  of  the  embryo. 

The  allantois  of  the  chick  now  gains  a  new  devel- 
opment and  an  altered  function.  In  the  case  of  the 
chick  it  floats  against  the  shell  of  the  egg  and  absorbs 
oxygen  through  the  shell.  Inside  the  body  of  the 
mammal  this  is  impossible,  because  the  air  is  too  far 
away.  No  shell  is  formed  about  the  Qgg  because  it 
is  not  to  be  laid.  The  tube  of  the  parent's  body  in 
which  the  Qgg  lies  becomes  thickened  at  the  point  of 
contact  with  the  egg.  It  grows  spongy  and  full  of 
blood  vessels.  Meanwhile  the  allantois  is  also  grow- 
ing spongy.  These  two  tissues  are  so  closely  pressed 
against  each  other  that  the  blood  vessels  of  the  trans- 


HOW    THE    MAMMALS   DEVELOPED  211 

formed  allantois  mesh  in  with  those  of  the  thickened 
parent  wall.  Thus  the  blood  vessels  of  the  mother 
are  brought  into  close  contact  with  those  of  her  off- 
spring. Her  blood  seeps  over  into  the  transformed 
allantois  which  is  now  called  a  placenta.  From  this 
it  is  handed  over  to  the  offspring,  which  thus  receives 
from  the  mother  her  blood,  and  returns  its  own  used 
blood  for  enrichment  and  purification.  So  the  allan- 
tois of  the  reptile  has  become  the  placenta  of  the 
mammal.  In  the  first  instance  it  served  only  as  an 
organ  of  respiration.  Now  it  has  come  to  supply  the 
embryo  with  rich  blood  containing  both  food  and 
oxygen  derived  from  the  mother.  After  the  offspring 
is  born  this  thickened  pad  breaks  loose,  and  subse- 
quently is  also  extruded  from  the  body,  forming  what 
is  known  as  the  afterbirth. 

Thus  far  we  have  spoken  of  the  change  in  the 
method  by  which  the  young  are  brought  to  such  a 
stage  of  development  that  they  can  stand  the  outer 
air.  One  of  the  improved  differences  between  the 
mammals  and  other  animals  lies  in  the  method  by 
which  they  nourish  their  young  for  some  time  after 
birth.  The  very  word  mammals  signifies  an  animal 
who  is  in  the  true  sense  of  the  word  a  mamma.  This 
name  for  mother  is  given  to  her  because  of  the  fact 
that  she  possesses  what  are  technically  known  as  mam- 
mary  glands,    or,    in   simpler  language,   breasts.      It 


212  THE    MEANING    OF    EVOLUTION 

would  seem  as  if  here  we  had  an  entirely  new  organ. 
No  other  animal  gives  nourishment  to  its  young  in 
such  fashion;  all  mammals  do.  What  is  the  origin 
of  the  habit?     How  did  the  organ  arise? 

A  part  of  an  animal's  body  that  has  the  power  to 
gather  material  from  the  blood  and  pour  it  out  in 
the  shape  of  fluid  is  known  as  a  gland.  Sometimes 
a  whole  organ  does  nothing  else.  Sometimes  small 
glands  are  scattered  through,  or  over,  the  surface  of 
another  organ.  There  are  two  kinds  of  glands  in  the 
skin  of  the  mammal.  The  best  known  and  most  fre- 
quently thought  of  are  those  which  pour  out  the  per- 
spiration. These  have  a  double  function.  In  the  first 
place  they  assist  in  keeping  the  temperature  of  the 
body  uniform.  When  we  are  too  warm  they  pour 
out  a  watery  fluid  over  the  surface  of  the  body.  If 
the  air  is  dry  enough  and  our  body  not  too  closely 
protected  by  clothing,  this  perspiration  passes  off  in 
the  form  of  vapor.  All  evaporation  requires  heat, 
which  in  this  case  is  extracted  from  the  body.  So 
soon  as  the  temperature  returns  to  its  normal  level 
the  flow  of  perspiration  ceases.  The  other  function 
of  the  sweat  glands  is  to  take  from  the  blood  some 
of  the  waste  matters  of  the  body  and  pour  them  out 
upon  the  surface.  This  is  done  in  order  that  the  body 
may  free  itself  from  substances  which,  if  they  were 
to  accumulate,  would  have  a  poisonous  effect  upon 


HOW    THE    MAMMALS   DEVELOPED  213 

its  action.  It  is  this  function  of  the  sweat  glands 
which  makes  it  necessary  for  us  to  bathe  the  surface 
of  our  bodies  with  water.  Dirt,  in  the  ordinary  sense 
of  the  word,  is  not  harmful  to  a  sound  skin.  Our 
reason  for  bathing  is  really  to  remove  the  wastes 
which  we  ourselves  have  poured  upon  the  surface  of 
the  skin.  These,  if  allowed  to  remain,  soon  decom- 
pose, like  all  nitrogenous  substances,  and  become  very 
offensive.  They  may  then  be  reabsorbed  into  the  skin 
and  nature's  effort  to  throw  them  off  has  been  in 
vain.  These  glands,  since  they  contain  waste  mat- 
ter, could  not  possibly  yield  food  for  the  young. 
They  would  poison  and  not  nourish.  Hence,  whatever 
the  breasts  may  be,  they  are  not  altered  sweat  glands. 
There  is  another  set  of  organs  in  the  mammalian 
skin.  At  the  base  of  each  hair  lies  an  oil  gland. 
The  function  of  these  is  to  pour  out  a  substance  which 
spreads  along  each  hair  and  over  the  surface  of  the 
body.  The  outside  of  the  skin  is  always  dead,  and 
would  easily  crack  were  it  not  for  the  constant  secre- 
tion of  this  oil.  In  winter,  when  the  blood  circulates 
less  freely  and  these  glands  consequently  pour  out  less 
oil,  the  supply  frequently  runs  short.  If  what  little 
is  poured  out  is  too  frequently  removed  by  washing, 
the  skin  becomes  brittle,  and,  on  bending  a  joint,  the 
epidermis  cracks.  The  gloss  of  the  hair  is  due  to 
the  oil  thus  poured  out.    This  oil  becomes  one  ingre^ 


214  THE    MEANING   OF    EVOLUTION 

dicnt  in  the  milk  produced  by  the  transformed  gland. 
But  there  is  another  important  constituent.  When 
one  does  unaccustomed  manual  work  the  ordinary  re- 
sult is  the  formation  of  a  Ijlister.  The  epidermis,  or 
scarfskin,  becomes  detached  from  the  dermis,  or  true 
skin,  and  the  space  between  the  two  rapidly  fills  with 
the  fluid  portion  of  the  blood,  known  as  lymph.  The 
fact  that  no  blood  vessels  have  been  broken  in  this 
detachment  results  in  there  being  no  red  corpuscles  in 
this  fluid.  Wherever  a  cavity  forms  in  the  body 
lymph   is   liable  to   enter   it. 

The  milk  glands  of  the  mammals  are  modified  oil 
glands.  The  fluid  which  they  now  pour  out  is  no 
longer  exactly  the  old  oil  with  the  addition  of  the 
lymph.  Undoubtedly  in  the  past  the  first  milk  was 
more  like  this  simple  mixture.  There  seems  no  doubt 
that  the  breasts  of  to-day  are  the  enlarged  and  modi- 
fied oil  glands  of  earlier  mammals.  In  one  of  the 
most  primitive  of  our  mammals  the  young  simply 
lick  certain  bare  spots  on  the  surface  of  the  mother's 
abdomen.  As  higher  forms  arise  there  develops  a 
smaller  or  larger  mound  with  a  distinct  projection, 
about  which  the  lips  of  the  offspring  can  easil}^  fasten. 
Lamarck  would  have  said  that  the  suction  of  the 
infant  had  produced  such  a  mound,  and  that  this  had 
been  transmitted  to  later  offspring  until  it  had  grown 
to  be  the  highly  developed  organ  we  now  find,  for  in- 


HOW    THE    MAMMALS    DEVELOPED  215 

stance,  in  the  cow.  Since,  however,  we  have  come 
to  disbeheve  in  the  transmission  of  acquired  charac- 
ters, this  explanation  will  no  longer  serve.  We  must 
content  ourselves  with  saying  that,  by  whatever  acci- 
dent the  nipple  arose,  the  success  of  it  when  present 
determined  its  selection  by  nature  and  its  consequent 
persistence.  With  increase  in  its  function  has  come 
increase  in  the  size  of  the  glands.  Lower  animals 
which,  like  the  hog,  produce  a  large  number  of  off- 
spring, possess  a  large  number  also  of  these  glands. 
With  the  diminishing  number  of  young  and  greater 
care  of  them  as  we  rise  in  the  scale  has  come  also  a 
diminishing  number  of  breasts  in  the  female.  Whether 
those  on  the  front  of  the  body  should  persist,  or  those 
on  the  rear,  depends  upon  other  factors  in  the  life 
of  the  animal.  Hoofed  animals,  perhaps  because  their 
best  weapon  is  the  hoof  and  they  can  there  best  pro- 
tect their  young,  have  retained  them  in  the  rear  of 
the  body.  In  the  group  of  animals  known  as  the 
primates,  including  monkeys,  apes,  and  man,  the  habit 
of  holding  the  young  in  the  arms  for  protection  has 
determined  the  persistence  of  the  breasts  upon  the 
chest  rather  than  the  abdomen. 

It  is  interesting  to  notice  that  the  habit  of  the  ele- 
phant of  protecting  its  young  by  means  of  its  tusks 
has  also  resulted  in  a  similar  position  of  the  milk 
glands. 


•^/^ 


2l6  THE    MEANING   OF    EVOLUTION 

That  the  primates  had  once  a  larger  number  of 
offspring  is  confirmed  by  double  evidence.  Even  to- 
day the  number  of  children  at  a  birth  is  often  two, 
sometimes  three,  rarely  four.  The  day  before  this 
was  written  came  the  report  of  a  case  of  five  children 
at  a  birth,  all  of  whom  seemed  sound  and  all  of  whom 
lived.  Still  more  direct  evidence  is  found  in  the  fact 
that  occasionally  in  the  human  female  there  are  two 
pairs  of  breasts,  and  very  rarely  three  pairs.  These 
are  then  disposed  in  a  double  line  down  the  front  of 
the  body. 

The  new  plan  of  caring  for  the  young  is  one  of  the 
priceless  heritages  of  the  higher  animals.  As  we  rise 
in  the  grade  of  life  the  number  of  the  young  pro- 
duced at  one  time  steadily  diminishes,  while  the  care 
spent  upon  them  increases.  The  shad  may  lay  four 
hundred  thousand  eggs  and  trust  them  entirely  to 
their  fate.  The  sunfish  will  lay  a  thousand,  by  no 
means  all  of  which  can  be  fertilized,  but  it  guards 
them  somewhat  after  deposition.  The  toad  lays  sev- 
eral hundred,  stores  them  with  a  considerable  amount 
of  nourishment,  and  protects  them  by  a  bitter  deposit 
of  mucous.  The  turtle  has  reduced  the  number  of 
eggs  to  perhaps  a  score.  Each  of  these  is  supplied 
with  abundant  nourishment,  so  that  the  young  may 
develop  to  considerable  size  and  activity  before 
emerging  from  the  egg.    This  material  is  enclosed  in 


HOW    THE    MAMMALS    DEVELOPED  2.\J 

a  firm  protective  shell  and  hidden  away  from  sight 
by  being  buried  in  the  ground.  In  the  mammals  com- 
paratively few  eggs  are  produced  at  one  time.  These 
are  fertilized  within  the  body  of  the  parent,  are  at- 
tached to  the  parent,  and  absorb  her  blood.  No  shell 
is  needed  because  nothing  will  kill  the  developing  off- 
spring that  is  not  likely  to  injure  the  parent.  Not 
only  do  the  young  feed  upon  the  blood  of  the  mother 
up  to  the  time  of  birth,  but  they  are  practically  de- 
pendent upon  this  same  blood  after  birth.  Though 
they  do  not  take  it  directly  from  the  veins,  the  milk 
is,  none  the  less,  the  transformed  blood  of  the  mother. 
This  assures  the  young  of  food  as  well  as  of  protec- 
tion. Best  of  all,  the  young  are  provided  with  the  } 
companionship  of  the  mother.  Now  for  the  first  time 
animals  learn  by  example.  Heretofore  they  have  been 
born  with  a  nearly  undeviating  instinct;  now  intelli- 
gence begins  to  arise.  They  can  imitate  their  mother. 
Heretofore  no  acquired  characters  affected  the  young. 
In  the  mammals,  although  the  young  cannot  inherit 
the  acquired  habits  of  the  parents,  they  can  get  them  . 
by  imitation,  which  serves  nearly  as  well.  J 

There  is,  however,  a  more  wonderful  advantage 
that  comes  from  the  close  attachment  between  mother 
and  offspring.  This  intimate  relationship  brings 
about  an  affection  of  the  mother  for  her  young  hereto- 
fore unknown  in  the  animal  world.     It  is  somewhat 


2l8  THE    MEANING   OF    EVOLUTION 

paralleled    among    birds,    but    here    the    care    of    the 
nestling  is  less  intimate,  far  less  maternal,  than  the 
care  of  the  mammal  for  her  young.     As  the  numberj 
of  the  young  grows  less  and  the  care  taken  of  them 
increases,  the  intensity  of  the  affection  also  increases. 
By  the  time  we  get  as  high  as  the  dog  or  the  cat  this 
fondness  becomes  a  fierce,  self-sacrificing  love.   When 
we  come  to  man,  with  his  high  intellectual  powers, 
with   his   deeper  moral   sense,   we  find  a   wonderful 
change.     This  love  of  the  mother  for  her  child  has 
grown  into  the  finest  emotion  possible  to  the  human 
heart.     It  no  longer  is  confined  to  the  dependent  life^ 
of  the  child,   but    follows  the   offspring  through   its 
entire   life,    guiding,    guarding,    shaping    its    destiny, 
handing  on  to  the  child  the  treasured  wisdom  of  the 
race.     Influenced  by  the  example  of  the  mother,  the"! 
father  comes  to  have  a  love  for  his  children.     It  is  ( 
not  so  strong  as  that  of  the  mother,  nor  so  utterly  j 
unselfish,  but  it  is  still   a  noble  and  exquisite  love.J 
Developing  in  a  different  direction,  the  love  of  the 
mother  for  her  children  grows  as  civilization  advances, 
and  spreads  over  the  father  of  those  children  as  well. 
Again  reflecting  her  love,  the  man  finds  himself  filled 
with  a  new  feeling  for  the  woman.     It  is  never  as 
unselfish,  as  free  from  desire,  as  is  her  love,  but  it 
completely  transforms  his  relation  to  her.     What  has 
been  with  him  simply  desire  is  ennobled  and  enriched 


HOW    THE    MAMMALS    DEVELOPED  219 

until  it  becomes  the  finest  passion  of  his  hfe,  abso- 
lutely transforming  him,  in  relation  to  her,  from  a 
selfish  brute  into  a  tender  and  lifelong  companion. 
So  utterly  does  the  love  thus  engendered  transfigure 
human  life  that  when  we  seek  to  express  the  divine 
nature  in  human  terms,  and  these  are  the  only  terms 
we  know  how  to  use,  the  richest  revelation  that  has 
come  to  us  is  the  conception  taught  by  the  Master  that 
"God  is  Love"  and  that  "as  a  father  pitieth  his  chil- 
dren, so  the  Lord  loveth  them  that  fear  him." 


CHAPTER   VIII 

iThe  Story  of  the  Horse 

Ever  since  men  have  been  familiar  with  the  idea 
of  evolution  there  has  been  a  temptation  on  the  part 
of  the  zoologist  to  draw  up  pedigrees  expressing  the 
relationship  between  the  various  groups  of  the  animal 
kingdom.  The  impulse  is  natural,  and,  if  the  result- 
ing tables  are  not  accepted  with  too  much  confidence, 
the  result  is  not  undesirable.  The  truth  of  the  matter 
is  that  all  of  these  pedigrees  are  more  or  less  hypo- 
thetical. They  simply  show  what  connection  seems 
most  likely.  In  all  of  them  are  spaces  filled  with 
doubtful  names.  Each  addition  to  our  acfjuaintance 
with  the  past  history  of  animals  necessitates  revision 
of  our  tables.  The  student  of  fossils,  trying  to  re- 
build in  imagination  the  world  of  the  past,  finds  him- 
self often  strangely  unable  to  link  these  animals  to- 
gether. The  result  is  that  the  more  we  know  of 
fossils,  the  more  distrustful  we  become  of  the  easy 
connections  we  have  been  making  between  groups. 
Accordingly   we    are    more   than    commonly   pleased 

when  we  find  the  clear  indication  of  a  genuine  pedi- 

220 


THE    STORY    OF    THE    HORSE  221 

gree,  actually  illustrated  by  real  examples,  following 
each  other  in  time  through  the  geological  history.  A 
few  of  these  lines  are  gradually  becoming  plain,  and 
none  of  them  is  clearer  than  the  pedigree  of  our  fa- 
miliar and  much  loved  horse.  The  example  is  a  par- 
ticularly interesting  one,  not  only  because  of  our  af- 
fection for  the  animal,  but  because  the  horse  origi- 
nated in  all  likelihood  in  North  America  on  the  land 
occupied  to-day  by  our  Western  plains.  As  though 
he  loved  the  country  of  his  ancestors,  he  returned 
after  having  circled  the  globe,  and  once  more  went 
wild  in  the  home  of  his  forefathers.  The  problem 
was  first  worked  out  in  Europe  and  later  elaborated 
in  this  country.  Now  the  history  gets  its  finest  ex- 
pression in  the  American  Museum  of  Natural  His- 
tory in  New  York  City.  The  collection  of  fossil 
horses  in  that  institution  surpasses  in  completeness 
and  in  excellence  of  mounting  and  of  sympathetic 
restoration  any  similar  collection  representing  the  an- 
cestry of  any  other  animal  in  the  world. 

In  the  table  of  Geological  Times,  given  in  chapter 
six,  the  era  of  recent  life  known  as  the  Cenozoic  is 
seen  to  occupy  something  like  five  million  years.  This 
figure,  as  w^as  previously  suggested,  is  very  uncer- 
tain, and  may  be  three  or  may  be  six,  but  is  safely 
represented  in  millions.  Through  most  of  this  time 
stretches  what  is  known  as  the  Age  of  Mammals,  the 


222  TTIE    MEANING    OF    EVOLUTION 

Tertiary  Age.  Its  close,  occupying  only  the  last  few 
huiuircd  thousand  years,  is  known  as  the  Age  of  Man, 
the  Quaternary.  Through  perhaps  three  or  four  mil- 
lions of  these  years  stretches  the  known  pedigree  of 
the  horse. 

W'lien  we  go  back  to  the  early  Tertiary  we  find  a 
forest,  with  trees  that  shed  their  leaves,  interspersed 
with  glades,  in  which  already  the  grasses  were  begin- 
ning to  be  developed.  This  state  of  affairs  had 
existed  but  for  a  comparatively  short  time,  geologi- 
cally speaking.  It  had  come  only  in  the  latter  part 
of  the  preceding  era.  Lake  and  swamp,  meadow  and 
forest  intermingled  to  make  a  rich  and  varied  scene. 
Slowly  the  land  toward  the  western  side  of  North 
America  lifted  itself  into  plateau  and  mountain  range. 
Slowly  the  westerly  winds  began  to  be  cut  off  by 
the  barriers  thus  raised  across  their  path.  As  they 
swept  over  the  plateau  and  down  into  the  eastern 
plain  their  moisture  came  to  be  diminished.  Grad- 
ually a  very  different  state  of  affairs  set  in.  The 
ground  became  harder,  the  forest  became  sparser,  the 
plants  became  higher  and  firmer,  the  grasses  tougher 
and  more  wiry,  and,  by  the  time  the  Quaternary  ar- 
rived, a  condition  probably  even  drier  than  that  of  to- 
day existed  over  our  western  highlands.  Throughout 
this  long  change,  spread  over  millions  of  years,  a  crea- 
ture which  has  become  our  horse  steadily  persisted 


THE    STORY    OF    THE    HORSE 


223 


and  steadily  advanced.  Side  lines  developed  which 
finally  disappeared,  but  the  main  line  kept  on,  and 
when  the  Quaternary  came  the  horse  arrived  with  it. 
Many  of  the  skeletons  in  this  series  were  known  be- 
fore it  was  realized  what  they  were.  As  time  went 
on  and  intermediate  forms  were  found,  it  became  pos- 
sible to  recognize  these  as  ancestors  of  the  horse  and 
to  assign  them  their  proper  position  in  the  family  tree. 


IVnat 


Wrist  - 


Jfter  H.  F.  Osborne  and  Charles  R.  Knight.       By  permission  of  the  American  Museum  of 
Natural  History. 

THE  EVOLUTION  OF  THE  HORSE'S  FOOT 


The  earliest  of  the  forerunners  of  the  horse  with 
which  we  are  acquainted  would  certainly  not  be  recog- 
nized as  such  by  any  but  the  most  careful  student  of 


224  THE    MEANING   OF    EVOLUTION 

animals,  if  we  could  see  him  to-day.  He  stood  not 
higher  than  a  fox-terrier  dog,  though  his  shape  was 
very  different.  But  he  would  probably  be  more  likely 
to  be  classed  with  the  dog  than  with  the  horse  by  the 
hasty  observer,  for  he  walked  with  four  toes  of  each 
foot  upon  the  ground  as  the  dog  does  to-day.  Like 
the  dog,  he  had  hanging  at  the  inner  side  of  his  front 
foot  a  little  useless  toe.  He  was  long  in  body,  com- 
paratively short  of  leg,  a  little  long  of  head  and  neck, 
and  distinctly  long  of  tail.  His  grinding  teeth  had 
points  on  them  not  unlike  a  pig's,  and  possessed  no 
apparent  resemblance  to  the  wonderful  curved  and 
ridged  surfaces  seen  on  the  teeth  of  the  modern  horse. 
What  his  skin  and  hair  were  like  can  only  be  con- 
jectured. In  the  restoration  which  Mr.  Knight  has 
made,  at  the  suggestion  of  Professor  Osborne,  an 
interesting  inference  has  been  drawn.  That  he  was  a 
creature  of  the  forest  is  suggested  by  his  spreading 
toes,  which  would  keep  him  from  sinking  in  the  soft 
soil.  It  is  consequently  surmised  that  he  was  dap- 
pled with  spots  which  allowed  him  to  rest  unnoticed 
on  the  sun-flecked  floor  of  the  forest.  Mane  he  had 
none,  and  his  tail  was  probably  tufted  slightly  at  the 
end  with  hairs,  which  were  increasingly  short  as  they 
approached  the  top.  He  had  no  forelock,  and  the 
hair  along  the  ridge  of  his  neck  was  a  little  longer 
than  the  rest,  and  stood  erect.     Browsing  about  on 


PHENACODUS,  AN  EARLY  GENERALIZED  MAMMAL. 

After  Henry  F.  Osborne  and  Charles  R.  Knight. 

By  permission  of  the  American  Museum  of  Natural  History. 


THE  DAWN  HORSE  (EOHIPPUS). 
After  Henry  F.  Osborne  and  Charles  R.  Knight. 
By  permission  of  the  American  Museum  of  Natural  History. 

[To  face  224J 


THE    STORY    OF   THE    HORSE  22 1^ 

the  soft  and  tender  herbage  of  his  woodland  home, 
his  teeth  had  as  yet  no  tendency  to  become  special- 
ized. The  molars  had  mounds  upon  them,  develop- 
ing, perhaps,  more  into  the  shape  of  the  points  of  the 
hog's,  but  even  still  quite  generalized  teeth.  His  main 
enemies,  from  v^hom,  perhaps,  he  could  with  little  dif- 
ficulty escape,  were  creatures  related  to  the  hyenas 
of  to-day.  Perhaps,  like  their  modern  representa- 
tives, they  preferred  eating  their  flesh  tainted  to  ex- 
erting themselves  enough  to  capture  and  kill  their 
prey.  By  the  time  we  advance  a  little  further  into 
the  Tertiary,  though  still  in  its  early  portion,  a  re- 
markable change  has  already  come  about.  The  fifth 
toe,  which  in  the  earliest  horse  hung  upon  the  side  of 
the  front  foot,  has  completely  disappeared.  The 
change  in  the  hind  foot  has  gone  still  further.  The 
hind  leg  in  many  animals  evolves  more  rapidly  than 
the  front.  The  heavy  work  of  running  is  always 
done  by  the  hind  feet,  while  the  front  feet  serve 
rather  as  a  prop  to  keep  the  animal  from  falling  than 
as  the  actual  means  of  locomotion.  Hence  the  hind 
feet  and  the  muscles  of  the  hind  quarters  are  almost 
always  heavier  than  the  front.  Possibly  on  the  front 
foot  the  little  fifth  toe  was  less  of  an  obstruction,  and 
jpersisted  after  the  early  horse  had  lost  the  corre- 
sponding toe  on  his  hind  foot.  This  process  has  gone 
on  still  further  in  this  second  stage,  and  the  hind  foot 


226  THE    MEANING    OF    EVOLUTION 

has  but  three  toes,  while  the  front  still  has  four.  This 
is  not  the  only  advance.  Already  the  middle  toe  of 
the  original  set  of  five  is  becoming  emphasized.  The 
weight  is  thrown  more  forcibly  upon  it,  as  with  the 
human  foot  it  is  upon  the  inner  or  big  toe.  The  mid- 
dle toe  is  growing  larger  and  larger,  and  the  nail 
upon  it  is  spreading  around  it  and  is  growing  firmer. 
The  creature,  too,  is  standing  more  nearly  upon  his 
toes;  his  legs  are  getting  longer;  he  stands  higher 
from  the  ground,  and  now  has  come  to  be  the  size  of 
a  hound. 

We  can  only  surmise  why  this  creature  should  have 
undergone  such  a  change,  but  the  presence  of  flesh- 
eating  animals  having  the  size  of  a  fox,  and  pre- 
sumably of  the  fox's  swiftness,  probably  tells  the 
story.  The  little  bands  of  early  horses,  pursued  by 
their  carnivorous  foes,  were  slowly  modified  into 
swifter  creatures.  It  is  not  so  much  that  running 
made  them  fast,  as  that  the  slow  ones  were  contin- 
ually being  caught.  If  this  process  of  constant  elimi- 
nation of  the  slow  members  of  any  herd  is  kept  up 
long  enough,  the  group  will  necessarily  develop  speed. 
As  time  goes  on,  of  these  early  horses  those  which 
happened  to  have  longer  legs  and  stood  higher  upon 
their  toes  won  In  the  race,  and  handed  on  their  quali- 
ties to  their  long-legged  descendants.  As  the  animal 
rose  upon  his  toes,  the  inner  toe,  corresponding  to  our 


THE    STORY    OF    THE    HORSE  227 

thumb,  was  first  raised  off  the  ground  and  rendered 
useless,  while  a  similar  change  came  over  the  corre- 
sponding toe  on  the  hind  foot.  The  hard  work  of 
running  being  done  on  the  latter,  this  superfluous  toe 
was  more  detrimental  there  than  on  the  front  foot, 
and  disappeared,  consequently,  more  rapidly.  In  time, 
however,  it  also  disappeared  from  the  front  foot. 
Gradually  the  further  elevation  of  the  foot  lifted  the 
toe,  which  corresponds  to  our  little  finger,  off  the 
ground,  and  this  now  disappears  also. 

With  increasing  toughness  of  the  grasses,  as  the  cli- 
mate becomes  drier  and  the  region  more  elevated,  the 
teeth  of  the  horse  are  given  harder  work.  The  points 
begin  to  spread  into  ridges  and  to  unite  with  each 
other  in  such  way  as  to  form  the  crescents,  which  are 
later  to  be  so  characteristic  of  the  teeth  of  the  modern 
horse. 

By  the  middle  of  the  Tertiary  this  ancestral  horse 
has  risen  in  height  until  he  is  taller  and  heavier  than 
a  setter  dog.  Three  toes  are  found  on  each  front  foot. 
The  middle  toe  is  getting  constantly  more  developed, 
though  the  smaller  toes  are  evidently  still  of  use. 
The  ridges  of  the  teeth  are  quite  crescentic  now  on 
the  outer  side,  and  becoming  better  adapted  to  the 
evidently  firmer  food  which  the  creature  is  obliged  to 
eat. 

As  we  come  toward  the  end  of  the  Tertiary,  the  de- 


228  THE    MEANING   OF    EVOLUTION 

velopmcnt  which  had  been  all  pointing  in  one  direc- 
tion has  advanced  very  much  further.  The  creature 
now  would  be  undoubtedly  recognized  by  anyone  as 
a  horse.  The  legs  are  longer  and  straighter ;  the  mid- 
dle toe  has  become  the  only  useful  toe,  though  on  each 
foot  a  smaller  toe,  slender  and  probably  useless,  still 
hangs  on  either  side.  Two  similar  useless  toes  to-day 
hang  at  the  back  of  the  foot  of  the  cow,  which  is 
now  walking  upon  her  two  toes,  which  give  her  the 
appearance  of  carrying  a  cloven  hoof.  That  is  to  say, 
the  first  toe  on  the  foot  of  the  cow  has  disappeared, 
the  second  and  fifth  hang  useless  and  much  dimin- 
ished at  the  back  of  the  foot,  while  the  third  and 
fourth  are  both  well  developed  and  serviceable  in 
walking. 

The  late  Tertiary  horse  has  grown  to  be  the  size 
of  a  burro  of  to-day,  though  probably  it  was  a  little 
more  slender.  The  teeth  are  quite  horselike,  both  in 
shape  of  the  crescentic  ridges  on  their  surface,  in  the 
length  of  the  teeth  in  the  jaw  bone,  and  in  the  fact 
that  the  crinkled  edges  of  enamel  on  the  upper  sur- 
face are  protected  on  either  side  by  dentine  or  by 
cement.  These  surfaces,  being  softer  than  the  enamel, 
wore  away  somewhat  more  rapidly  and  allowed  the 
sharp  edges  of  enamel  to  stand  up  in  ridges.  This 
plan  increases  the  grinding  power  of  the  teeth. 

With  the  oncoming  of  the  Era  of  Man  the  horse 


THE  THREE-TOED  HORSE  (MESOHIPPUS). 

After  Henry  F.  Osborne  and  Charles  R.  Knight. 

By  permission  of  the  American  Museum  of  Natural  History. 


THE  AMERICAN  HORSE  (EQUUS). 
After  Henry  F.  Osborne  and  Charles  R.  Knight. 
By  permission  of  the  American  Museum  of  Natural  History. 

(To  face  228] 


THE   STORY  OF  THE   HORSE  229 

reaches  his  modern  splendid  development.  During 
the  early  Quaternary  the  horse  was  perhaps  in  some 
of  his  representatives  a  larger  creature  than  he  is  to- 
day. Each  foot  now  has  but  a  single  toe.  The  nail 
has  spread  around  firmly  and  heavily,  until  it  has  be- 
come a  splendidly  developed  hoof,  permitting  the  ani- 
mal to  travel  with  speed  over  firm  and  often  stony 
ground.  The  side  toes  have  disappeared  completely 
from  the  outside  of  the  horse's  leg,  although  upon  re- 
moving the  skin  it  is  easy  to  find  the  long  splints, 
which  are  the  remnants  of  toes,  which  have  not  yet 
quite  disappeared.  His  heel  has  been  lifted  in  the  air 
until  it  is  eighteen  inches  off  the  ground,  and  he  is 
standing  like  an  expert  dancer  upon  the  tip  of  his  toe. 
The  body  of  the  horse  thus  being  lifted  far  off  the 
ground,  a  new  development  becomes  necessary.  All 
through  the  growth  of  the  creature  the  neck  and  head 
have  been  obliged  to  lengthen  correspondingly.  Every 
animal  must  be  able  to  bring  its  head  down  to  the 
level  of  its  feet  in  order  that  it  may  drink.  Various 
animals  use  different  methods  to  accomplish  this  re- 
sult. The  giraffe,  with  his  enormously  long  legs,  has 
a  correspondingly  long  neck,  which  lowers  his  mouth 
to  the  ground.  Even  with  this  extended  neck  the 
giraffe's  legs  are  so  exceedingly  long  that  he  is  obliged 
to  spread  his  front  feet  when  he  wishes  to  reach  tlic 
ground  with  his  head.     The  elephant  has  pursued  ex- 


230  THE    MEANING    OF    EVOLUTION 

actly  tlie  reverse  plan.  Using"  his  tremendous  head  as 
a  battering-  ram  in  lighting,  and  using  his  enormous 
tusks  l)oth  in  battle  and  in  uprooting  young  trees,  a 
lengthened  neck  is  absolutely  out  of  the  question. 
Furthermore  his  front  teeth  have  grown  so  prodi- 
giously that  they  would  interfere  with  his  getting  his 
mouth  to  water.  Accordingly,  his  nose  has  length- 
ened its  tip  until  it  reaches  the  level  of  his  feet,  and 
this  nose  becomes  to  him  the  main  organ  of  gras[^ 
and  of  touch.  To  drink,  its  end  is  inserted  in  the  pool 
and  water  is  drawn  up  the  nostril.  If  the  animal  were 
to  attempt  to  draw  it  all  the  way  back  into  his  throat, 
it  would  inevitably  strangle  him  by  getting  into  his 
windpipe.  Accordingly,  when  the  nose  is  well  filled 
with  water,  the  tip  of  it  is  inserted  in  his  mouth,  and 
the  water  discharged  by  a  quick  puff.  The  horse  has 
taken  a  method  intermediate  between  these.  It  had 
moderately  lengthened  both  neck  and  head  in  order 
to  get  to  the  ground  with  its  nipping  teeth,  and  thus 
to  gather  the  grasses  which  serve  as  its  principal  food. 
The  mammalian  teeth,  while  of  four  kinds,  really 
in  most  animals  serve  but  two  purposes.  The  front 
teeth  consist  of  the  incisors  and  canines,  and  are  used 
for  biting.  The  hind  teeth,  consisting  of  premolars 
and  molars,  are  used  for  grinding.  In  the  horse,  the 
jaw  has  lengthened  between  these  two  sets,  carrying 
the  biting  teeth  far  forward  of  the  molars.     It  is  this 


THE    STORY    OF    THE    HORSE  23 1 

gap  in  the  row  of  the  horse's  teeth  which  makes  it 
possible  for  us  to  insert  the  bit  into  his  mouth. 

Now  comes  a  strange  accident  into  the  Hfe  of  our 
American  horse.  Creatures  of  the  same  kin  had  been 
evolving  in  Europe  and  Africa,  but  the  developments 
are  more  distinctly  horselike,  it  would  seem,  in  our 
own  country.  Then  for  some  reason  the  horse  disap- 
peared completely  from  American  soil.  Doubtless 
two  things  happened.  First  of  all,  some  of  them  mi- 
grated across  a  stretch  of  open  country  which  then 
connected  America  with  Asia  in  the  neighborhood  of 
Bering  Strait.  These  creatures  spread  first  over  Asia 
and  then  over  Africa  and  Europe,  leaving  their  skele- 
tons scattered  over  this  enormous  stretch  of  country. 
Asses  and  zebras  are  still  found  abundantly  and  widely 
scattered,  but  the  wild  horse  of  to-day  is  seen  only  in 
western  Asia.  What  happened  to  those  who  remained 
in  America  we  shall  possibly  never  know.  Some  sur- 
mise that  a  fly  not  unlike  the  tsetse-fly  of  Africa 
killed  them  out.  Perhaps  the  members  of  the  cat  fam- 
ily, which  are  steadily  growing  larger  and  fiercer,  fed 
on  their  young  if  not  upon  the  older  ones,  and  ex- 
terminated them.  Perhaps  the  Glacial  period  which 
followed  was  too  cold  for  them.  But,  whatever  may 
have  been  the  cause  these  horses  died  out  not  only  in 
North  but  also  in  South  America,  to  which  country 
they  had  spread. 


232  TITE    MEANING   OF    EVOLUTION 

The  old  world  horse  was  the  companion  of  man. 
The  skeletons  of  those  found  with  early  man  in  the 
caves  of  Europe  look  as  if  the  horse  had  been  a 
creature  to  draw  man's  burdens  and  to  serve  him  for 
food,  rather  than  to  bear  him  upon  its  back.  Its 
roasted  bones  are  often  found  about  the  old  tribal 
fires.  Upon  the  discovery  of  the  new  world  the  Span- 
iards brought  with  them  to  Mexico  and  to  the  Mis- 
sissippi Valley  the  horses  which  carried  them  in  their 
battles  against  the  Indians.  In  the  course  of  these 
frays  many  riders  were  killed  and  their  horses  roamed 
wild.  Slowly  they  made  their  way  to  the  western 
plains ;  gradually  they  became  tougher  and  more  wiry ; 
their  diminished  hoofs  learned  to  catch  more  carefully 
in  the  rocks  of  their  mountain  home;  and  the  mus- 
tang and  bronco  of  more  recent  years  are  the  de- 
scendants of  the  little  dawn  horse,  whose  dainty  skel- 
eton is  found  in  the  rocks  over  which  his  later 
descendants,  after  a  long  stretch  of  perhaps  four 
million  years,  are  now  running. 


J 


CHAPTER  IX 

Evolutionary  Theories  Since  Darwin 

In  considering  the  value  of  Charles  Darwin's  work 
and  its  permanent  effect  upon  the  thought  of  man- 
kind, we  must  be  careful  to  distinguish  between  two 
phases  of  his  effort.     It  was  his  aim  to  prove  two    ^ 
propositions :   first,  that  there  is  such  a  process  as  evo- 
lution; second,  that  he  had   discovered  the   method 
by  which  evolution  is  accomplished.     Before  his  time 
there  was  no  general  agreement  as  to  the  fact  of  evo- 
lution.    People  generally  thought  the  idea  absurd,  as 
well  as  irreligious.    All  previous  efforts  on  the  part  of 
advanced  thinkers  to  persuade  mankind  of  the  truth 
of  evolution  had  been  nearly  without  effect.     Among 
the  early  philosophers  the  whole  idea  was  purely  spec- 
ulative.    They  made  no  attempt  to  prove  it,  and  the 
conception  was  without  influence  upon  the  thinking 
of  the  ordinary  man.     This  remains  true  until  the 
time  of  Lamarck.     This  French  genius  succeeded  in 
persuading  not  a  few  people  of  the  validity  of  the 
idea  of  evolution.    He  probably  could  have  convinced 
many  more  had  it  not  been  for  the  hostility  of  Cuvier. 

233 


234  THE    MEANING    OF    EVOLUTION 

Accordingly,   Charles   Darwin's  "Origin  of   Species'* 
fell  upon  a  world  entirely  hostile  to  the  idea,  when  it 
thought  of  it  at  all.    Within  fifty  years  of  the  publica-   . 
tion  of  this  wonderful  book,  probably  the  entire  sci-^ 
entific  world  is  agreed  that  evolution,  in  some  form 
or  other,  is  the  undoubted  solution  of  the  mystery  of 
creation.     The  materialist  may  think  of  it  as  a  me-    J 
chanical  process  relentlessly  working  itself  out  with- 
out design  or  purpose.     The  theist  will  accept  it  as 
the  plan  by  wdiich  Eternal  Power  steadily  works.   The 
devout  Christian  or  Jew  will  see  in  it  God's  method  of 
creation.     The   idea  of   development  has   penetrated  , 
every  science  that  has  to  do  with  animals  or  man.     It 
is   even   beginning   to    inlluence   such    inorganic   sci- 
ences as  Physics  and  Chemistry.     We  now  hear  of 
the  evolution  of  the  elements,  and  the  evolution  of 
forces.    The  world  has  been  persuaded  that  evolution 
is  true,  and  this  is  primarily  the  result  of  the  work  of  , 
Charles  Darwin.     It  is  astonishing  that  so  great  a 
revolution  should  have  come  in  so  short  a  time. 

The  other  phase  of  Darwin's  work  was  his  attempt 
to  find  the  agent  which  is  bringing  about  the  actual 
transformation  of  animals  and  plants.  As  we  have 
seen  in  the  preceding  chapters,  it  was  his  idea  that 
natural  selection  was  the  efficient  agent  which  con- 
stantly eliminated  all  unfit  variations,  leaving  only  the  ., 
best  to  carry  on  the  work  of  the  world  and  to  repro- 


EVOLUTIONARY    THEORIES    SINCE   DARWIN        235 

duce  their  own  fit  kind.  Many  biologists  since  his 
time  have  doubted  whether  unaided  Natural  Selec- 
tion will  account  for  the  constant  advance  in  orean- 
isms.  This  is  the  part  of  the  work  which  is  often 
seriously  questioned. 

Weissman  and  his  co-workers  have  contended  that 
this  unaided  principle  will  serve.    Most  biologists  have 
asked  for  some  more  efficient  cause,  and  assert  that  se- 
lection does  not  account  for  the  appearance  of  varia-   . 
tions,  but  only  for  their  preservation,  and  that  any 
valid  theory  of  evolution  must  show  how  variations 
originate.     It  is  chiefly  in  this  respect  that  Darwin's 
work    has    failed    to    satisfy    many    later   biologists. '' 
When  we  hear  a  scientist  speak  of  Darwinism  as  be- 
ing dead,  this  is  what  he  means.     He  does  not  think 
evolution  false,  but  believes  that  Natural  Selection  is 
not  sufficient   to  account   for  evolution.     There  are 
three  main  difficulties  involved   in  Darwin's  theory.. 
The  chief  defect  lies  in  the  fact  that  selection  cannot  * 
originate  varieties.     In  all  his  earlier  works  Darwin  -" 
simply  accepted  variations  as  he  found  them.    He  was 
content  to  say  that  all  species  varied  constantly,  and 
in  every  direction.     He  gave  no  theory  to  account  for 
variation.     Whenever  he  took  measurements  of  the 
dimensions  of  any  large  series  of  objects  of  the  same 
kind  he  found  these  measurements  to  vary,  apparently, 
in  all  directions.     Upon  the  facts  of  these  variations, 


236  THE    MEANING    OF    EVOLUTION" 

and  witliont  accounting"  for  them,  he  bnilt  his  own 
theory  of  evokition.  lie  realized  his  weakness,  and 
acknowledged  it  in  his  book.  He  probably  did  not 
anticipate  how  insistently  later  biologists  would  de- 
mand an  explanation  that  would  account  for  this 
variation.  In  his  later  work,  responding  to  this  criti- 
cism, Darwin  originated  a  theory  which  he  called 
Pangenesis.  He  believed  that  when  an  adult  animal 
had  responded  to  his  environment  and  acquired  a  new" 
character  he  could  transmit  this  character  to  his  off- 
spring. At  that  time  no  one  doubted  this  fact.  The 
whole  theory  of  Lamarck  was  based  on  the  assump- 
tion that  this  could  be  done.  Darwin  suggested  thaf 
every  organ  of  the  body  threw  off  minute  particles, 
which  he  called  pangenes.  These  little  bodies,  car- 
ried by  the  blood,  were  taken  up  by  the  egg  cells  or 
sperm  cells,  and  the  latter  cells  determined  the  future 
development.  Consequently,  the  character  of  the  new 
individual  was  determined  by  the  parental  pangenes. 
In  this  way  the  gain  acquired  by  one  generation  could 
be  passed  on  to  the  next.  This  theory  was  purely 
speculative.  He  never  pretended  that  there  was  the 
faintest  corroborating  evidence  visible  to  the  micro- 
scope in  the  organ,  in  the  blood,  or  in  the  germ  cell. 
It  was  not  an  accounting  for  what  is,  but  for  what  it 
seemed  possible  to  him  might  be. 

This  theory  of  Pangenesis,  in  the  shape  in  which   > 


EVOLUTIONARY   THEORIES   SINCE  DARWIN        237 

Darwin  promulgated  it,  has  dropped  out  of  congidera- '" 
tion  almost  entirely.     DeVries  of  recent  years  has  re- 
vised it,  but  with  distinct  modifications,  and  most  bi- 
ologists pay  no  attention  to  it. 

There  is  a  school  of  biologists,  headed  by  Weiss- 
man,  who  have  come  to  be  known  as  Neo-Darwinians.^ 
These  men  have  insisted  that  Natural  Selection,  if 
properly  understood  and  developed,  is  quite  sufficient 
to  account  for  the  fact  of  evolution,  including  the  ap- 
pearance of  variations.  Weissman  himself  is  a  micro- 
scopist  of  more  than  common  skill.  He  is  thoroughly 
accomplished  in  the  most  modern  methods  of  killing,' 
fixing,  staining,  and  mounting.  This  worker's  ac- 
quaintance with  the  intimate  structure  of  the  cell  is 
probably  as  great  as  that  of  any  other  man  in  the 
world.  Weissman  asserts  that  he  has  seen  inside  the 
nucleus  all  the  machinery  necessary  to  explain  how 
the  father  hands  over  his  qualities  to  his  children.  He  y 
insists,  equally  strongly,  that  this  process  is  such  that 
no  father  can  hand  to  his  child  any  qualities  which 
he  himself  did  not  have  at  least  in  potentiality  at  his 
birth.  Everything  the  individual  acquires  during  his 
lifetime  is  his  own  possession,  which  he  may  use  and 
develop  to  the  utmost  extent,  but  it  dies  with  him.  -^ 
His  children,  born  after  he  possesses  it,  can  no  more 
inherit  it  than  those  born  before.  Weissman  ex- 
pressed this  in  his  famous  statement  that  "There  is 


238  THE    MEANING   OF   EVOLUTION 

no  inheritance  of  acquired  characters."  The  biologi- 
cal world  has  had  no  shock  equal  to  this  since  Dar- 
win's time,  and  there  are  few  other  questions  to  which 
scientists  to-day  return  with  such  constant  vigor. 

If  what  Weissman  says  is  true,  that  no  variation 
or  development  which  comes  to  an  animal  during  his 
lifetime  can  be  transferred  into  his  own  germ  cells 
and  handed  on  to  his  children,  then  it  becomes  evi- 
dent that  we  must  find  some  cause  of  variation  that 
acts  within  the  germ  cells.  This  is  the  difficulty 
which  Weissman  meets.  He  says  that  there  are  small 
particles  in  the  nucleus  of  each  cell;  that  these  par- 
ticles which  he  calls  determinants  decide  the  form  and 
the  course  of  development  of  that  cell;  that  when  that 
cell  divides  to  produce  another  cell  it  gives  to  this 
other  cell  one-half  of  each  determinant.  As  a  result 
the  second  cell  grows  to  be  like  the  first.  This  tells  us 
why  offspring  are  like  their  parents.  There  is  noth- 
ing in  the  theory  thus  far  to  show  us  why  offspring 
are  not  exactly  like  their  parents.  In  other  words, 
there  is  no  accounting,  thus  far  in  the  theory,  for 
variation.  When  the  biologist  studies  carefully  the 
history  of  an  egg  while  it  is  being  formed,  he  sees 
that  at  one  stage  in  its  development  it  throws  away 
not  one-half  of  each  determinant,  but  one-half  of  the 
determinants.  When  an  egg  does  this,  it  deliberately 
casts  aside  one-half  of  the  possibilities  of  its  own  de- 


AUGUST  WEISMANN 
(i834—  ) 
Student  of  the  mechanism  of  heredity. 


[To  face  238] 


EVOLUTIONARY    THEORIES    SINCE   DARWIN        239 

velopment.  This  throwing  away  is  quite  as  effective 
for  all  its  descendants.  Any  ancestral  quality  now 
lost  is  lost  from  the  line  forever.  In  the  formation 
of  the  sperm  cell  set  free  by  the  male  a  similar  throw- 
ing away  of  one-half  the  characters  has  taken  place. 
The  Qgg  cell  and  the  sperm  cell  fuse  together.  There 
are  as  many  possibilities  now  as  there  were  in  either 
parent,  but  not  all  the  potentialities  of  both  parents. 
Half  the  possibilities  of  each  have  been  thrown  away, 
and  hence  cannot  appear  in  the  offspring.  By  this 
constant  process  we  get,  in  every  generation,  new 
combinations  of  qualities.  This  is  the  main  cause, 
says  Weissman,   for  variations. 

There  is,  however,  another  possible  cause.  Each 
cell  has  enough  determinants  in  it  for  many  indi- 
viduals, and  it  seems  to  be  more  or  less  a  matter  of 
accident  which  qualities  shall  come  out.  It  has  been 
suggested  that  as  an  tgg  lies  within  the  gland,  a 
blood  vessel  may  bring  blood  to  it  in  such  way  that 
a  determinant,  lying  in  a  certain  position  in  the  egg, 
may  get  the  richest  supply  of  blood,  and  hence  de- 
velop at  the  expense  of  the  less  nourished  determi- 
nant. By  these  two  methods  variation  comes  into 
an  animal's  life,  if  Weissman  and  his  school  are  to 
be  believed. 

This  is  a  serious  blow,  if  true,  to  many  theories  of 
evolution.     The  great  mass  of  evolutionists  still  feel 


240  THE   MEANING   OF   EVOLUTION 

that  somehow  there  is  an  influence  by  which  the 
environment  produces  variation.  How  the  influences 
of  the  surrounding  world  can  get  down  into  the  body 
of  the  parent  and  affect  the  egg  is  unknown.  This 
is  freely  confessed  by  every  biologist.  All  are  agreed 
tliat  Weissman's  work  has  made  us  cautious,  and  pre- 
vented our  lightly  accepting  a  belief  in  the  influence 
of  the  environment.  Yet  it  is  felt  by  many  that  slowly 
and  gradually,  in  the  long  run,  the  germ  is  affected 
in  the  same  manner  as  is  the  body  of  the  parent.  In 
other  words,  even  those  who  are  not  followers  of 
Weissman,  have  accepted  the  idea  that  there  is  little 
inheritance  of  acquired  characters.  Yet  they  return 
to  the  belief  that  somehow,  in  some  way  as  yet  un- 
explainable,  the  main  cause  for  variation  in  animals 
lies  in  the  situation  in  which  they  live,  and  tends 
toward  better  adaptation  to  that  situation. 

Whether  men  with  this  conviction  are  merely  re- 
actionaries whose  confidence  is  returning,  or  bold 
thinkers  whose  views  will  ultimately  prevail,  time 
alone  can  tell. 

A  second  strong  objection  was  brought  against  the 
theory  of  Natural  Selection.  Darwin  declared  that 
small  variations  in  favorable  directions  are  selected 
and  become  the  starting  point  of  new  and  better 
things.  It  is  soon  seen,  however,  that  the  effect  of 
unaided  Natural  Selection  would  be  but  to  mix  new 


EVOLUTIONARY    THEORIES    SINCE   DARWIN        24 1 

departures  with  the  old  forms,  and  soon  swamp  out 
any  progressive  tendency.  Whenever  a  genius  ap- 
peared, instead  of  finding  a  corresponding  genius 
with  which  to  pair,  it  mated  with  the  average  of  its 
own  species.  Hence  its  offspring  were  nearer  the 
average  than  it  was,  and  their  offspring  still  nearer. 
Thus  whatever  advantage  the  genius  originally  pos- 
sessed gradually  sank  into  the  common  level. 

It  was  Moritz  Wagner,  a  German  naturalist,  who 
first  insisted  that  if  favorable  variations  were  to 
amount  to  anything  these  possessors  must  not  only 
mate  with  others  of  their  same  kind,  but  must  also 
be  prevented  from  mating  with  the  old  average 
group.  Accordingly,  the  belief  arose  that,  under 
ordinary  circumstances,  variations  returned  to  the 
common  level.  Wherever  a  varying  group  became 
separated  by  any  barrier  from  mating  with  the  rest 
of  its  species,  and  had  only  its  own  kind  to  pair  with, 
a  new  species  sprang  up.  This  barrier  might  be  a 
desert,  or  an  impassable  mountain  range,  an  arm  of 
the  sea,  or  anything  else  that  the  animal  could  not, 
or  would  not,  cross.  Isolated  in  this  way,  the  little 
group  that  had  an  advantage  in  a  different  direction 
could  develop  its  tendencies,  and  a  new  species  would 
be  made  of  what  had  been  previously  only  a  geo- 
graphical race.  In  this  matter  of  geographical  iso- 
lation  Wagner    is   very    strongly    supported   by   the 


2.|2  THE    MEANING    OF    EVOLUTION 

American  zoologist,  David  Starr  Jordan,  who  be- 
lieves tliat  no  two  closely  related  species  of  animals 
ever  occupied  the  same  geographical  area.  Both 
V/agner  and  Jordan  are  ardent  admirers  of  Darwin 
and  his  theory  of  natural  selection,  but  both  believe 
that  it  is  necessary  to  add  the  idea  of  isolation  in 
order  to  make  natural  selection  effective. 

George  John  Romanes,  a  British  naturalist,  has 
added  to  W^agner's  idea  of  isolation,  the  expanded 
conception  that  there  may  be  isolations  that  are  not 
geographical.  For  this  phase,  Romanes  has  coined 
the  term  physiological  isolation.  Something  in  the 
structure  or  habit  of  the  animals  with  the  new  vari- 
ation prevents  them  from  mating  with  the  older  type. 
Occasionally  it  is  a  difference  in  the  structure  of  the 
reproductive  organs  themselves.  This,  however,  is 
not  the  only  possible  divergence.  The  mating  sea- 
son in  one  group  may  come  earlier  than  that  of  the 
other,  or  may  come  during  the  day,  while  the  main 
group  is  in  the  habit  of  mating  at  night.  Anything 
which  keeps  some  members  of  a  species  separate  in 
their  mating  from  the  rest,  will  result  in  the  course 
of  a  longer  or  shorter  time,  says  Romanes,  in  the 
formation  of  a  new  species. 

A  third  great  objection  was  raised  against  Dar- 
winism. The  theory  said  that  only  useful  variations 
were  selected  by  nature.     It  was  asserted  by  objectors 


EVOLUTIONARY    THEORIES    SINCE   DARWIN        243 

that  the  earliest  beginnings  of  any  variation  must 
be  too  sHght  to  be  useful,  or  as  the  term  went,  to 
have  selective  value. 

It  has  been  noticed  by  a  number  of  naturalists  that 
certain  animals  seem  to  carry  the  development  of  a 
peculiarity  altogether  too  far.  It  is  seen  for  instance 
that  in  the  Irish  Elk,  which  has  for  some  time  been 
extinct,  the  horns  were  so  enormous  as  to  be  a  source 
of  danger  rather  than  of  assistance  to  their  owner. 
It  was  said  that  the  tendency  to  produce  heavy  horns 
had  gained,  as  it  were,  a  sort  of  momentum,  and  that 
this  impulse  had  carried  the  development  beyond  a 
safe  limit.  The  Irish  Elk  became  extinct  because  his 
horns  were  too  heavy.  During  the  Mesozoic  period 
the  reptiles  grew  too  large.  They  seemed  to  have 
carried  size  to  a  point  at  which  it  became  a  danger 
instead  of  a  help.  They  completely  passed  out  of 
existence,  leaving  behind  them  only  very  much 
smaller  reptiles. 

Eimer,  of  Germany,  has  based  on  facts  like  these 
his  theory  of  Orthogenesis.  He  says  that  variations 
in  animals  are  not  indefinite  and  in  every  direction, 
but  that  they  follow  along  clear  and  definite  lines. 
These  lines,  in  the  case  of  the  elk  and  of  the  Meso- 
zoic reptiles,  developed  too  far,  but  ordinarily  the 
effect  of  such  a  tendency  is  distinctly  lieneficial  to 
the  animal.     It  particularly  assists  in  carrying  on  for 


244  THE    MEANING   OF    EVOLUTION 

a  lime  the  variations  which  have  not  yet  become  use- 
ful to  the  animal.  It  has  always  been  difficult  on 
Darwinian  principles  to  understand  how  the  begin- 
nings of  the  useful  variations  could  be  selected  before 
they  were  strong  enough  to  be  of  actual  value  to  the 
animal.  This  tendency  to  variations  in  certain  di- 
rections instead  of  at  random  would  account  for  such 
early  development.  This  theory  of  Orthogenesis  has 
not  figured  very  strongly  in  the  history  of  the  move- 
ment, but  it  recurs  at  intervals. 

Both  in  America  and  France  there  is  a  constant  j 
tendency  on  the  part  of  zoologists  to  return  to  the 
Lamarckian  idea  that  it  is  the  use  of  an  organ  that 
develops  it,  its  disuse  that  makes  it  fade  away.  This 
is  undoubtedly  true  of  the  individual,  and  although 
Weissman  insists  that  it  is  useless  to  the  species  as  a 
whole,  many  zoologists  are  slow  to  relinquish  entirely 
the  idea  that  somehow  these  favorable  developments 
become  reproduced  in  the  offspring. 

Professor  Cope,  the  American  paleontologist,  was 
a  strong  believer  in  the  effect  of  activity,  both  upon 
the  individual  and  upon  his  descendants.  He  believed 
that  the  insistent  beating  of  the  foot  of  an  animal 
upon  the  hard  soil  of  the  drying  Tertiary  plateau, 
had  influenced  the  production  of  a  firmer  nail,  which 
spread  around  the  entire  end  of  the  toe  and  made 
the  hoof  of  the  ungulate.     He  believed  that  the  use 


EVOLUTIONARY    THEORIES    SINCE   DARWIN        245 

of  the  teeth  in  grinding  produced  a  stronger  and 
better  molar  tooth,  and  that  the  offspring  shared  in 
this  advantage.  Since  Weissmann's  time,  however, 
every  Lamarckian  feels  it  necessary  to  suggest  some 
method  by  which  the  altered  body  of  the  parent  can 
produce  modifications  in  the  germ  plasms  from  which 
the  young  are  to  spring.  One  of  our  later  biologists 
begins  to  talk  of  some  effect  comparable  with  wire- 
less telegraphy  or  induced  electricity.  He  believes 
that  organs  in  the  adult,  not  necessarily  by  direct 
action,  but  by  action  from  a  distance,  may  alter  the 
germ.  Of  this,  there  is  no  proof  at  present.  Others 
have  suggested  that  just  as  the  ductless  glands  pour 
into  the  blood  chemical  substances  which  materially 
affect  the  growth  and  development  of  other  portions 
of  the  body^  so  similar  enzymes,  or  other  chemical 
substances,  may  be  sent  into  the  blood,  which  sub- 
sequently bathes  the  germ  cells  of  the  coming  gen- 
eration and  produces  the  change.  But  of  this,  again, 
there  is  no  proof.  We  may  believe  that  acquired 
characters  are  transmitted,  but  we  certainly  do  not 
have  a  very  clear  idea  as  to  how  it  can  be  done. 

One  of  the  strongest  objections  to  Darwin's  idea 
of  evolution  by  natural  selection  of  small  and  favor- 
able variations,  is  that  the  process  is  too  inconceiva- 
bly slow  to  account  for  the  enormous  progress  which 
has  been  made.    The  answer  has  always  been  that  our 


24<J  THE    MEANING    OF    EVOLUTION 

observation  ran  back  so  short  a  time  that  we  really 
have  no  clear  idea  of  how  rapid  evolution  may  have 
been.  Again,  it  has  been  answered  that  transitional 
geological  periods,  in  which  there  is  much  change  in 
the  physical  geography  of  a  country,  will  produce 
more  rapid  evolution  than  we  at  present  are  experi- 
encing. 

Hugo  DeVrics,  of  Amsterdam,  believes  he  has 
found  the  answer  to  this  difficulty.  Outside  of  his 
botanical  garden  an  American  species  of  Evening 
Primrose  had  run  wild.  In  looking  over  a  number 
of  these  plants  he  found,  every  here  and  there,  cer- 
tain peculiar  members  of  the  species.  They  differed 
noticeably  to  the  practiced  eye  from  the  rest  of  the 
group.  When  they  were  planted  and  crossed  with 
each  other,  and  the  resulting  seeds  were  again  planted, 
the  peculiarity  remained  constant  in  all  the  members 
of  the  collection.  Here  then  we  have  a  true  varia- 
tion, not  large  in  amount,  but  at  the  same  time  quite 
definite,  and  which  from  the  first  remains  true.  Here 
are  the  beginnings,  says  DeVries,  of  new  species. 
They  are  true  from  the  first;  they  can  live  among 
other  members  of  the  species  and  still  come  true; 
they  do  not  need  isolation,  at  least  in  Wagner's  geo- 
graphical sense.  These  forms  DeVries  calls  muta- 
tions. It  is  his  thought  that  a  species  may  run  along 
uniformly   for  a  long  time   when,   from  some  cause 


HUGO  DE  VRIES 

Advocate  of  evolution  by  leaps. 


[To  face  246.J 


J 


EVOLUTIONARY    THEORIES    SINCE    DARWIN        247 

which  he  has  not  determined  as  yet,  instability  comes 
into  the  species  and  it  varies  in  quite  a  number  of 
directions.  Each  of  these  variations  may  be  the  start- 
ing point  of  a  new  species.  DeVries  believes  that 
he  has  at  least  half  a  dozen  mutants  of  his  new  Even- 
ing Primrose. 

This  theory  of  Mutation  has  been  eagerly  seized 
upon  by  many  botanists.  The  zoologists  have  not 
accepted  it  quite  so  enthusiastically.  If  this  is  the 
chief  method  by  which  species  transform,  it  seems 
strange  that  we  do  not  find  more  mutations  than  we 
do.  Perhaps  we  do  not  look  carefully  enough;  per- 
haps we  shall  find  them  a  little  later.  Just  at  present 
it  seems  premature  to  believe  that  all  evolution  is 
by  mutation,  although  quite  possibly  some  of  it  is. 
The  main  apparent  advantage  of  mutation  is  that  it 
hastens  the  time  in  which  a  new  species  may  arise. 

There  are  certain  difficulties  which  run  back  into 
the  problem,  and  which  must  first  be  reasonably 
solved  before  a  clear  understanding  of  the  idea  of 
evolution  is  possible.  The  first  of  these  is  as  to  the 
nature  of  life.  What  is  life?  The  reply  of  the  biolo- 
gist will  probably  be  that  so  far  as  its  material  side 
is  concerned,  it  must  be  answered  in  terms  of  physics 
and  chemistry.  As  to  any  side  not  material,  if  it 
have  any  such  side,  science  says  that  the  chemist  can 
have   nothing   to   say.      The   chemist   may   have   an 


248  THE    MEANING    OF    EVOLUTION 

opinion  of  his  own  based  on  some  other  ground  than 
his  chemistry,  but  so  far  as  he  is  a  chemist,  he  has 
no  opinion.  The  chemical  side  of  Hfe  is  being  very 
carefully  and  very  fully  investigated.  We  are  cer- 
tainly being  brought  nearer  to  the  borders  of  the 
living  substance.  We  are  rapidly  gaining  fuller 
knowledge  of  the  physical  and  chemical  processes 
which  constitute  life,  or  with  which  life  is  always  as- 
sociated. If  we  gain  this  knowledge  we  shall  be  in 
better  position  to  solve  many  of  our  other  problems. 
Even  then  there  is  a  problem  which  preceded  and 
which  will  possibly  always  defy  solution.  How  did 
life  originate?  Has  it  developed  out  of  chemical 
and  physical  activities  which  we  know  as  heat,  light 
or  electricity?  If  so,  what  were  the  conditions  under 
which  it  developed?  If  we  understand  the  nature  of 
life,  and  the  conditions  under  which  it  developed,  we 
may  be  able  to  produce  it  at  will. 

A  few  scientists  may  hope  dimly  that  this  will 
be  attained.  I  suspect  a  great  majority  believe  it 
to  be  impossible,  and  that  the  question  as  to  whether 
life  evolved  upon  this  planet,  or  this  planet  became 
infected  with  life  through  meteoric  dust  from  some 
other  center,  will  forever  remain  an  unsolved  prob- 
lem. 


CHAPTER   X 

The  Future  Evolution  of  Man  "* 

The  disturbance  of  mind  created  by  the  publica- 
tion of  Charles  Darwin's  "Origin  of  Species"  would 
have  amounted  to  nothing  if  the  theory  had  been  ap- 
plied to  the  lower  animals  alone.  Few  people  would -J 
have  disputed  that  a  cow  and  a  buffalo  had  descended 
from  the  same  ancestor,  or  that  monkeys  and  apes 
were  of  a  common  blood.  The  whole  theory  would' 
have  been  looked  upon  by  those  outside  the  biologi- 
cal world  as  entirely  an  academic  question,  in  which 
they  had  little  concern,  and  less  interest.  But  within 
this  century  the  scientist  has  so  persuaded  the  world 
of  the  unity  underlying  the  activities  of  the  universe, 
that  so  soon  as  a  principle  is  established  men  begin 
to  run  it  out  to  the  very  end.  Everyone  knows  per-"" 
fectly  well  that  if  it  could  be  proved  that  the  dog 
and  the  horse  had  a  common  ancestor,  still  more  if  it 
could  be  made  apparent  that  the  dog  and  the  frog 
and  fish  had  sprung  from  the  same  stock,  then  there 
could  be  no  question  of  what  would  be  the  final  ap- 
plication  of  the  theory.     Man  himself  could  be  no 

249 


250  THE    MEANING    OF    EVOLUTION 

exception  to  the  law.  So  the  battle  dropped  at  once 
upon  this  most  interesting  point,  and  around  this  cen- 
ter the  contest  has  waged.  , 

What  is  the  origin  of  man?     Who  are  his  ances- 
tors?    As  soon  as  we  ask  the  question  there  is  no 
doubt  whatever  as  to  the  answer,   if  we  accept  the 
principle  of  evolution.     Our  only  means  of  judging 
relationship  between  animals  is  by  the  similarity  of 
their  structure.     As  soon  as  we  come  to  examine  the 
other   creatures    even    in   the   most   cursory    fashion, 
there  is  only  one  group  which  in  any  close  degree  re- 
sembles  the    human    species.      Our   nearest    relativesj 
among  living  animals  must  undoubtedly  be  the  apes^ 
Some  little  distance  farther  away  stand  the  monkeys,  -^ 
and,   structurally  speaking,   there   is  more  difference 
between  a  monkey  and  an  ape  than  there  is  between 
an  ape  and  man.    The  gap  between  man  and  his  rela- 
tives of  this  group,  known  as  the  primates,  is  a  men- 
tal, not  a  physical  one.    While  his  brain  and  his  mind  ♦ 
have   developed    far   beyond   theirs,    the   rest   of   his 
body  is  comparatively  close  to  that  of  an  ape. 

Probably  no  one  can  face  the  possibility  of  his 
being  descended  from  creatures  not  unlike  the  ape, 
without  feeling  a  stirring  sense  of  repugnance.  The 
least  aristocratic  of  us  hesitates  to  name  in  the  line 
of  his  ancestry  creatures  so  unlike  himself  as  the 
members  of  this  group.     It  seems  to  us   impossible 


THE   rUTURE   EVOLUTION    OF    MAN  25 1 

that  we  should  have  descended  from  creatures  as 
lowly  as  they.  If  evolution  is  true,  these  are  among 
our  near  ancestors.  Back  of  the  group  of  primates 
lies  a  far  less  developed  set  of  insectivorous  animals, 
behind  them  the  reptiles,  behind  them  the  fishes. 
When  we  get  back  this  far  we  are  less  certain  but 
most  probably  the  worms  take  up  the  story.  So  our 
ancestry  runs  back  to  the  very  beginning,  when  it 
originated  in  the  one-celled  animals  which  are  also 
the  ancestors  of  all  the  rest  of  the  animal  world.  If 
we  are  inclined  to  deny  our  ancestors  in  the  trees, 
what  shall  we  say   of  our   forefathers   in  the  seas? 

The  question  of  course  is  not  to  be  decided  by  our 
likes  or  our  dislikes.  If  the  evolution  of  man  is  true 
it  will  not  make  it  less  true  because  the  process  is 
not  to  our  liking.  It  is  our  part,  if  this  be  the  truth, 
to  accept  it  as  we  do  any  other  truth.  Surely  those 
of  us  who  are  moral  of  thought  are  not  willing  to 
disbelieve  a  truth  because  it  is  unpleasant. 

The  newness  of  the  idea  is  the  chief  reason  for  . 
our  dislike  of  it.  This  lowliness  of  origin  should 
not  be  distasteful  to  us.  Nothing  about  Abraham 
Lincoln  seems  to  us  more  wonderful  than  that  a 
man  who  towered  head  and  shoulders  above  his 
generation,  indeed  above  most  generations  of  men, 
in  his  fineness  of  life,  in  his  nobility  of  purpose,  in 
the  integrity  of  his  aims,  should  have  been  of  ex- 


V 


J 


252  THE   MEANING   OF   EVOLUTION 

cecdingly  humljle  extraction.  It  only  adds  to  the 
glory  of  his  later  achievements  that  he  should  have 
lived  in  a  cabin,  have  spent  his  young  manhood  split- 
ting rails  and  running  a  flat-boat,  and  have  gained 
his  education  almost  unaided  from  a  few  books  and 
much  meditation  in  front  of  a  log  fire. 

That  the  greatest  military  General  on  the  Union 
side  of  the  Civil  war  should  have  been  the  son  of 
a  country  tanner,  and  as  a  boy,  not  over-shrewd  in 
the  matter  of  bargains,  adds  to  the  glory  of  his  later 
life.  The  simplicity  of  his  childhood  gives  new  lus- 
ter to  the  power  with  which  he  led  the  forces  of  a 
nation  to  victory,  and  then  went  to  a  battle  no  less 
noble  in  his  long  fight  for  honor  while  suffering  from 
disease  and  approaching  death.  Why  then  should 
we  feel  that  such  beginnings  in  the  lower  world  are  V 
too  humble  for  man?  Why  do  we  think  his  present 
superiority  diminished  by  his  lowly  origin?  Why 
can  we  not  see  that  precisely  the  reverse  is  true?  The 
more  humble  the  level  from  which  he  sprang  the  j 
more  gloriously  creditable  is  his  present  position. 
Instead  of  being  ashamed  of  having  risen  from  the 
brute,  it  should  be  the  glory  of  man  that  he  has  so 
sprung.  His  chief  superiority  lies  in  the  fact  that 
while  they  have  remained  where  they  are,  he  has  so 
completely  outdistanced  them  as  to  have  placed  a 
gap   between   himself   and   them   that    seems   almost 


THE    FUTURE    EVOLUTION    OF    MAN  253 

impassable.     Furthermore,    if  man  with  his  present 
glory  of  intellect  and  of  moral  impulse,  has  sprung 
from   a   creature   whose   superiority   to   the   ape   lay 
chiefly  in  its  potentialities,  then  it  does  not  yet  appear 
what  he  shall  be.     We  can  judge  the  future  only  by 
the  past.    Through  the  long  ages  the  development  has 
been  very  slow.     Through  the  last  hundred  thousand 
years  the  development  of  man  has  been  wonderfully 
rapid,  compared  with  v/hat  went   before,   though   it 
seems   slow   enough   when   we   look   at   it   from   the 
standpoint  of  our  historical  and  traditional  reports. 
But  with  this  added  impulse,  this  rapid  improvement 
that  has  come  with  the  development  of  mind  instead 
of  muscle,  of  tooth  and  of  claw,  we  have  every  prom- 
ise of  an  evolution  that  shall   far  surpass  anything 
that  has  yet  come.     To-day  our  leaders  are  way  be- 
yond the  average  of  the  mass.    Who  shall  doubt  that 
in  a  not  too  distant  to-morrow,  the  masses  shall  be 
where  the  leaders  of  to-day  now  are.     We  shall  not 
then  have  reached  a  dead  level  of  superiority.     Our 
leaders  will  have  moved  on  as  rapidly  as  have  the 
masses,  and  will  be  as  far  ahead  of  them  then  as 
they  are  now.     It  shall  be  their  work  to  apprehend 
new  virtues,  and  to  work  them  out  in  their  lives.   The 
masses,  seeing  the  beauty  of  the  lives  of  the  leaders, 
recognizing  in  those  lives  the  revelation  of  the  divine 
power  which  they  have  apprehended,  will  hunger  to 


/ 


254  THE    MEANING    OF    EVOLUTION 

learn  of  them  and  to  lead  lives  like  theirs.  To  this 
process  who  shall  set  an  end?  The  advance  is  slow, 
as  in  all  evolution;  but  anyone  who  wishes  to  do 
so  may  easily  detect  the  direction  of  the  current. 

The  evolution  of  man's  physical  frame  probably 
has  nearly  ceased.  Gradually  organs  that  are  use- 
less to  him  are  passing  away.  Slowly  his  hands  are  r 
becoming  more  delicate  and  refined  and  skilled.  But 
his  evolution  has  begun  to  work  itself  out  on  en- ' 
tirely  other  lines.  We  sometimes  hear  that  the  men 
of  the  past  were  the  full  equivalent  of  the  men  of 
to-day.  Scholars  like  to  tell  us  that  the  population 
of  Athens  was  finer  in  cjuality  than  any  population 
that  has  existed  since.  We  must  remember  that 
group  after  group  of  men  may  be  expected  to  special- 
ize intellectually  and  fail  to  develop  morally  and 
physically.  Under  these  conditions  this  little  branch 
of  the  human  race  runs  through  its  forced  flower- 
ing and  comes  to  an  end.  With  the  study  of  history 
and  the  earnest  investigation  of  these  lives  of  the 
past,  new  possibilities  arise  within  the  human  family. 
The  next  race  that  flowers  may  take  longer  to  decay 
because  it  understands  better  the  weaknesses  that  car- 
ried away  the  preceding  civilization.  In  time  there 
will  arise  a  civilization  that  understands  the  past. 
A  whole  people  will  some  time  realize  that  intel- 
lectual development  alone  will  not  save  it,  or  Athens 


THE    FUTURE    EVOLUTION    OF    MAN  255 

would  have  lasted;  that  moral  development  alone  will 
not  suffice,  or  Judcea  had  been  permanent ;  that  physi- 
cal development  will  not  serve,  or  Sparta  would  stand 
to-day.  Some  day  there  will  arise  a  nation  that  will 
see  to  it  that  every  intellectual  advance  is  accom- 
panied by  an  equivalent  moral  and  physical  advance. '- 
When  this  time  comes  we  shall  have  a  race  which 
can  survive.  Are  we  to  be  that  race?  The  sins  of 
man  are  generally  the  dregs  of  his  brute  ancestry. 
Bestiality  of  life  was  once  common  enough  to  at- 
tract no  attention.  Kings  and  nobles  were  not  sup- 
posed to  be  clean  so  long  as  they  confined  their  bestial 
relations  to  those  below  them  in  rank.  Gradually 
men  are  becoming  ashamed  of  uncleanness  in  life. 
I  Some  day  there  will  be  no  difference  so  far  as  purity 
'  of  life  is  concerned,  between  the  two  who  present 
themselves  at  the  altar  asking  the  blessing  of  God 
on  their  union. 

If  anyone  doubts  that  English  speaking  people 
are  becoming  cleaner  of  life  he  needs  only  to  consult 
the  literature  of  the  past.  No  one  dreams  of  find- 
ing fault  with  Chaucer  because  his  stories  related  in 
the  company  of  men  and  women  often  would  not 
bear  such  telling  to-day.  Shakespeare,  with  all  his 
wonderful  genius,  needs  expurgating  if  one  would 
read  him  aloud  comfortably  to  a  mixed  audience. 
And   these   are   the   shining   stars.      When   we   drop 


*c» 


256  THE    MEANING    OF    EVOLUTION 

below  them,  the  literature  of  their  time  becomes 
nearly  impossible  to  read.  Fielding  and  Smollett  and 
Stern  helped  to  build  up  the  English  novel,  but  the 
stories  they  tell  speak  of  the  grossness  of  their  time 
in  language  that  is  unmistakable.  We  are  by  no 
means  clean  to-day.  A  fair  proportion  of  our  novels 
leave  much  to  be  desired.  The  stage  is  the  scene  of 
much  we  could  wish  to  see  cleaner.  Above  all  this 
grossness  there  towers  a  sweetness  and  beauty  of 
thought,  and  an  earnestness  of  purpose,  a  sincerity 
of  effort,  which  makes  the  present  time  fuller  of 
moral  purpose,  fuller  of  the  desire  to  be  clean  and 
to  help  others  to  be  clean,  than  graced  any  previous 
period  in  the  history  of  either  England  or  ^Vmerica. 
[JJnder  the  change  from  country  to  city  life  man 
has  suffered.  Here  too  evolution  is  necessary.  City 
life  tells  hard  on  the  second  generation  and  nearly 
destroys  the  third ;  but  we  have  come  to  understand 
the  difficulty  and  are  fast  remedying  it.)  It  is  more 
than  possible  that  the  next  generation  will  see  such 
changes  in  the  life  of  the  worker  in  the  great  center, 
as  shall  effectively  stop  the  physical  deterioration 
that  has  come  to  the  city  dweller.  God  grant  that 
modern  civilization  has  had  teaching  enough  and 
learned  its  lesson  well  enough.  God  grant  further 
that  we  may  give  over  slaughtering  our  most  am- 
bitious and  vigorous  young  men  in  battle  to  settle 


THE    FUTURE    EVOLUTION    OF    MAN  257 

questions  which  battle  can  never  settle.  God  grant 
that  we  have  come  to  a  turning  of  the  ways  where 
the  life  of  men,  women  and  children,  no  matter 
how  humble  their  station,  shall  stand  higher  in  value 
than  the  profits  of  any  commercial  venture.  God 
grant  that  we  will  soon  be  firm  enough  to  declare 
that  a  business  which  can  only  live  by  sacrificing 
the  health  and  strength  of  the  workers  must  be 
counted  an  unprofitable  business,  and  be  allowed  to 
cease.  God  grant  finally  that  the  American  people 
may  learn  from  the  past  to  guard  against  a  like  fate 
in  the  future;  that  here  may  be  the  people  whose 
strength,  intelligence  and  uprightness  shall  lead  the 
world;  not  for  the  sake  of  exceeding  the  world,  but 
with  the  high  mission  of  setting  to  the  world  an  ex- 
ample of  what  can  come  to  a  vigorous,  free  and  God- 
fearing people. 

In  the  early  history  of  the  evolution  of  man  the 
struggle  almost  always  concerns  the  individual. 
Gradually  the  family  comes  to  be  the  fuller  unit. 
Only  that  is  success  which  leads  to  the  success  of 
this  higher  group.  After  a  time  the  family  broadens 
to  the  tribe,  and  then  the  tribe  to  the  nation.  The 
evolution  of  social  institutions  is  at  present  going 
on  at  an  enormously  rapid  rate.  Throughout  the  civ- 
ilized world  democracy  is  coming  to  its  own.  Even 
where  the  form  of  monarchy  still  prevails,  the  sub- 


258  THE    MEANING    OF    EVOLUTION 

jects  of  the  monarch  are  having  more  and  more 
rights.  The  people  of  England  are  surely  as  free 
as  are  the  people  of  the  United  States.  Increasingly  \ 
all  forms  of  government  will  secure  for  all  their  sub- 
jects, no  matter  what  their  station  in  life,  a  fair  share 
of  the  general  prosperity.  In  this  field,  human  evo- 
lution is  perhaps  more  rapid  than  in  any  other. 

Any  individual  human  being  is  a  network  of  traits 
and  peculiarities.  He  has  all  the  ordinary  attributes 
of  humanity,  but  to  the  whole  complex  he  gives  an 
individual  peculiarity  which  is  totally  his  own. 
Where  did  he  get  his  cjualities?  In  the  earlier  times 
the  fairies  were  supposed  to  have  blessed  him  or 
cursed  him  in  his  cradle.  A  later  age  saw  in  the 
stars  the  rulers  of  man's  destiny.  He  was  jovial,  or 
saturnine,  or  martial,  depending  on  the  planet  which 
was  in  the  ascendant  at  the  time  of  his  birth.  Now 
we  know  "it  is  not  in  our  stars  but  in  ourselves  that 
we  are  underlings."  Everything  a  man  is  comes  to 
him  from  within  or  from  without;  from  nature  or 
from  nurture ;  from  his  heredity  or  from  his  en- 
vironment. From  our  ancestors  we  get  all  the  pos- 
sibilities of  our  lives.  To  a  certain  extent  we  are 
slaves  to  our  heredity,  but  not  by  any  means  to  any 
such  extent  as  to  make  us  hopeless,  unless  oiu*  hered- 
ity is  miserably  bad.  To  the  great  mass  of  us  come 
larger  potentialities  than  we  ever  develop,  and  such 


THE    FUTURE    EVOLUTION    OF    MAN  259 

possibilities  of  degradation  as,  fortunately,  few  of 
us  ever  reach.  Within  an  enormously  wide  range, 
man  is  the  architect  of  his  own  fortune.  Only  such 
traits  develop  as  find  a  stimulus  in  the  environment. 
Accordingly,  a  very  large  proportion  of  the  develop- 
ment a  man  may  achieve  depends  upon  the  cir- 
cumstances under  which  he  is  placed,  or,  what  is 
far  more  to  the  point,  in  which  he  may  place  him- 
self. Man  is  not  the  blind  sport  of  a  relentless  des- 
tiny. It  is  his  to  choose  his  environment;  it  is  his 
to  modify  his  environment  when  he  cannot  leave  it. 
To  an  extent  which  no  other  animal  has  ever  ap- 
proached, man  is  the  arbiter  of  his  own  destiny.  A 
hypothetical  ass  may  stand  helpless  between  two 
equidistant  bales  of  hay,  but  no  human  being  is  ever 
so  helpless  a  sport  of  his  environment.  As  it  is,  he 
may  drift  or  he  may  rove  as  he  pleases.  To  one 
man  the  current  may  be  stronger  than  to  another. 
There  may  be  now  and  then  a  child  so  feeble-minded 
as  to  be  unable  to  decide  the  course  of  its  own  life. 
It  will  not  be  long  before  society  will  see  to  it  that 
such  a  life  leaves  behind  it  no  strain  cursed  with  its 
fatal  weakness.  In  this  effort  to  advance,  man  has 
all  the  advantage  that  comes  from  concentrated  social 
effort.  No  man  may  live  to  himself.  To  every  man 
in  our  community  who  desires  it,  a  helping  hand  will 
be  stretched.     Often  a  hand  will  be  stretched  to  him 


26o  THE    MEANING    OF    EVOLUTION 

and  he  will  be  steadied  whether  he  will  or  not,  until 
his  own  will  reforms  itself  and  gains  the  mastery. 
Inasmuch  as  all  that  is  in  man  comes  from  his 
environment  or  from  his  heredity,  the  only  way  in 
which  the  race  of  men  can  be  advanced  is  by  improv- 
ing their  environment  or  by  bettering  their  heredity. 
The  first  of  these  is  the  province  of  the  sociologist; 
the  second  that  of  the  eugenist.  The  sociologist  has 
for  some  time  been  giving  his  careful  attention  to 
the  improvement  of  the  environment.  In  every  large 
city,  a  man  must  build  for  himself  a  house  fit  to  live 
in,  if  he  build  it  at  all.  Whether  he  erects  it  for 
himself  or  for  another  makes  no  difference.  Society 
will  no  longer  allow  him  to  build  a  home  which  is  a 
detriment  to  the  one  who  lives  in  it.  Not  only  must 
he  make  himself  a  decent  home  but  he  must  keep  it 
in  decent  condition.  The  community  will  not  allow 
him  to  endanger  his  own  health,  or  that  of  his  neigh- 
bor, by  an  insufficient  method  of  attending  to  his 
garbage,  or  by  a  lack  of  ordinary  cleanliness.  If 
he  will  not  clean  his  premises  himself,  the  law  sees 
to  it  that  they  are  cleaned  for  him.  Already  we 
are  beginning  to  understand  that  no  man  has  a  right 
to  employ  another  man  or  woman  or  child  at  wages 
which  are  not  sufficient  to  maintain  the  one  thus  em- 
ployed. The  wages  of  many  people  are  exceedingly 
meager,  notably  those  of  women  and  children.     He 


THE    FUTURE   EVOLUTION    OF    MAN  261 

can  read  but  ill  the  signs  of  the  times  who  does  not 
foresee  an  early  end  to  the  exploiting  of  the  labor  of 
these  helpless  creatures.  Humanity  has  determined 
firmly  that  these  things  must  pass,  that  the  young 
child  must  not  labor  long  or  hard,  that  a  woman 
must  not  be  taxed  beyond  her  strength.  Already  ^^ 
in  England  there  is  a  partially  successful  movement 
which  will  doubtless  spread  to  this  country  to  pro- 
vide that  a  woman  be  granted  a  little  time  before  and 
after  the  birth  of  her  child  during  which  she  shall 
not  be  allowed  to  suffer  because  her  power  to  earn  a 
wage  is  temporarily  gone.  These  things  cannot  fail 
in  the  long  run  to  strengthen  the  people.  They 
strengthen  chiefly  the  present  generation.  The  blight 
of  the  fact  that  acquired  characters  cannot  be  trans- 
mitted, meets  us  here.  This  improved  environment 
can  only  slowly,  if  at  all,  improve  the  race,  and  every 
effort  made  in  this  direction  must  be  repeated  with 
each  generation. 

Under  such  circumstances  is  it  to  be  wondered  at 
that  the  eugenist  is  hoping  to  raise  the  strain?  Any 
improvement  he  can  bring  about  is  not  only  valuable 
for  the  generation  in  which  it  comes  but  is  carried  on 
into  the  generations  which  follow.  This  is  the  hope 
that  strengthens  and  sustains  him  in  his  effort.  The 
science  of  eugenics  is  so  new,  so  little  is  surely  known 
concerning  the  transmission  of  human  characters,  that 


262  THE    MEANING    OF    EVOLUTION 

no  one  is  able  as  yet  wisely  to  say  what  course  is 
to  be  pursued  in  improving  the  race.  But  the  prob- 
lem is  so  interesting  and  its  outcome  so  overwhelm- 
ingly important  that  men  will  never  cease  striving  to 
know,  and  may,  before  many  years,  begin  wisely  to 
guide  us  in  our  efforts  to  provide  a  finer  stock. 

Heretofore  our  efforts  at  improving  the  strain  have 
been  confined  to  cattle,  chickens  and  plants.  An  al- 
most unalterable  repugnance  rises  as  soon  as  we 
speak  of  improving  the  human  strain.  Visions,  if 
not  stories,  start  up  at  once,  of  experimental  matings 
of  human  beings,  and  of  all  other  unspeakable  abomi- 
nations which  no  decent  man  expects  to  happen  or 
even  wishes  to  attempt.  If  there  is  one  thing  in  hu- 
man society  the  value  of  which  has  been  demon- 
strated through  the  unending  ages,  it  is  the  mono- 
gam  ic  marriage.  All  ideal  workers  must  point  to 
the  life-long  union  of  a  strong,  vigorous,  clean- 
minded  and  clean-lived  man  with  a  similarly  fine, 
strong,  clean-minded  and  clean-lived  woman.  Such 
an  ideal  may  be  slow  in  its  attainment,  but  he  aims 
too  low  who  aims  to  secure  anything  less  than  this. 
The  long  struggle  out  of  bestiality  into  pure  monog- 
amy has  been  so  slow,  so  gradual,  so  noble  in  its 
attainments,  and  is  still  so  far  from  perfection,  that 
it  would  be  an  inconceivably  stupid  blunder  to  let 
go   a   single  point   that   has   been  gained.      Whether 


THE    FUTURE   EVOLUTION    OF    MAN  263 

divorce  shall  be  allowed  to  remedy  a  mistake  may  be 
a  matter  of  dispute,  but  at  best  it  is  a  bad  remedy 
for  a  mistake  that  should  never  have  been  made.  No 
ideal  society  could  ever  consider  divorce  as  any  per- 
manent portion  of  its  activities.  Children  are  not 
like  cattle.  It  is  not  simply  a  question  of  their  being 
brought  into  the  v^orld  sound  and  strong.  Their 
long  infancy  which  in  the  biological  as  well  as  in  the 
legal  sense,  lasts  until  they  are  grown  up,  should  be 
spent  in  surroundings  which  can  minister,  by  ex- 
ample and  precept,  to  moral  and  intellectual  develop- 
ment. Surely  no  such  end  can  possibly  be  attained 
when  man  and  woman  mate  lightly,  to  part  quickly. 
At  first  sight  it  would  seem  a  wise  thing  to  require 
health  certificates  for  those  who  would  be  married. 
I  doubt  not  the  Chicago  Bishop  who  declined  to 
marry  his  parishioners  except  under  such  conditions, 
will  exert  a  beneficial  effect  upon  the  country  by 
the  attention  he  thus  attracts  to  the  subject.  It 
would  be  a  bad  day  for  the  city  if  all  the  clergy  and 
all  the  other  authorities  who  are  authorized  to  sol- 
emnize marriage  should  take  this  step.  We  have 
not  yet  arrived  at  such  a  stage  of  development  that 
a  marriage  certificate  is  essential  to  mating,  and  a 
restriction  of  this  sort  would  simply  mean  that  there 
could  be  no  legitimate  union  except  of  those  in  strong 
health.     To  the  burden  of  ill  health  would  be  added 


264  THE    MEANING    OF    EVOLUTION 

the  still  worse  handicap  of  an  illegitimate  parentage, 
with  all  its  bitter  train  of  scorn  and  shame.  Ac- 
cordingly, it  must  be  possible  before  the  law  for 
those  who  are  not  thoroughly  vigorous  to  marry. 
But,  year  by  year,  we  may  come  nearer  accomplish- 
ing a  finer  mating  by  the  aims  and  purposes  we  foster 
in  the  growing  generation.  Marriages  will  never  be 
worth  while  when  they  are  not  freely  entered  into 
by  the  contracting  parties.  Choice  must  be  free  and 
unrestricted  if  it  is  to  last  for  life;  but  this  does  not 
mean  that  it  must  be  unguarded.  It  w^ould  be  bitter 
folly  for  parents  to  leave  to  their  children,  without 
attempt  to  influence  or  restrain,  the  making  of  their 
marriages.  The  mating  of  our  children  must  be  in- 
spired, not  directed. 

There  is  one  taint  from  which  society  has  the 
right  and  the  duty  of  freeing  itself,  so  far  as  in  its 
power  lies.  This  is  the  taint  of  feeble-mindedness. 
Of  all  the  calamities  that  can  befall  a  human  being, 
feeble-mindedness  is,  perhaps,  the  worst.  From  most 
misfortunes  it  is  possible  to  recover;  with  most  of 
the  rest  one  may  exist  without  detriment  to  the  race. 
To  be  feeble-minded  simply  means  to  hark  back  to 
the  level  of  our  animal  ancestors,  without  regaining 
their  power  to  guide  life.  The  animal  is  provided 
with  a  bundle  of  instincts  which  tell  him  what  to 
do  in  all  the  ordinary  emergencies  of  life.     The  hu- 


THE   FUTURE   EVOLUTION    OF    MAN  265 

man  species,  in  its  development,  has  lost  a  large  por- 
tion of  its  instincts,  and  has  gained,  instead,  the 
power  of  intelligent  choice  and  the  ability  to  learn 
by  imitation.  When  these  drop  away,  man  without 
his  instincts  or  his  intelligence  is  more  helpless  than 
the  brute.  Students  of  sociology  are  making  clear 
to  us  that  a  large  portion  of  the  criminality  of  the 
world,  much  of  the  looseness  of  life,  and  a  large 
part  of  the  alcoholic  excesses  are  due  to  this  taint  of 
feeble-mindedness.  Recent  investigations  have  made 
it  clear  that  one  feeble-minded  family  in  a  commu- 
nity may,  in  the  course  of  years,  poison  the  life  of 
an  entire  state.  The  Jukes  family  in  New  York,  the 
Kallikak  family  in  New  Jersey,  have  shown  the 
awful  possibilities  of  descent  from  a  single  feeble- 
minded ancestor.  Prisons,  almshouses,  and  houses 
of  shame  owe  their  population  in  no  small  degree  to 
this  bitter  curse.  It  will  not  be  long  before  society 
will  learn  to  protect  itself  against  such  poisoning  of 
the  human  stock.  Nothing  is  more  clear  to  the  in- 
vestigator of  this  subject  than  that  the  one  over- 
whelming cause  for  feeble-mindedness  is  feeble- 
mindedness  in   the  parentage. 

There  is  one  type  of  mental  weakling,  known  as 
the  Mongolian  idiot,  which  may  arise  right  out  of 
the  heart  of  an  apparently  sound  family.  But  the 
number  of  these  is  comparatively  small.     The  num- 


266  THE    MEANING    OF    EVOLUTION 

ber  of  feeble-minded,  who  are  feeble-minded  because 
of  their  heredity,  is  dishearteningly  and  astonishingly 
large.  Every  attempt  to  examine  large  numbers  of 
school  children  shows  a  sickening  proportion  of 
those  who  are  distinctly  feeble.  Every  little  commu- 
nity seems  to  have  its  boy  or  girl  who  is  what  is 
known  as  silly.  Such  people  rarely  live  long  lives 
without  leaving  behind  them  feeble-minded  children, 
no  small  proportion  of  whom  are  likely  to  be  ille- 
gitimate. Against  this  fouling  of  the  stream  at  its 
source,  society  must  protect  itself.  (^Legislators  re- 
volt at  the  somewhat  inhuman  but  certainly  safe 
method  of  surgically  preventing  the  possibility  of  the 
feeble-minded  becoming  parents.  It  would  be  more 
creditable  and  just  as  effective  if  society  would  take 
upon  itself  the  tremendously  expensive  task  of  caring 
for  all  its  feeble-minded  in  institutions  during  their 
entire  life.  The  cost  would  be  large  for  a  genera- 
tion, but  would  rapidly  diminish  and  eventually  be- 
come small.  It  certainly  would  be  the  humane  way. 
These  people  in  good  institutions  are  by  no  means 
unhappy.  Within  the  limit  of  their  capacities  they 
can  do  many  things.  Wise  management  usually  will 
secure  from  them  labor  enough  of  wholesome  and 
simple  kind  nearly  to  pay  for  their  own  support. 
Nothing  could  be  better  for  them  than  to  till  the 
soil,   care   for  the  cattle,   tend  the  chickens,   and,   in 


THE    FUTURE   EVOLUTION    OF    MAN  267 

this  way,  provide  very  largely  the  materials  on 
which  they  are  fed.  How  this  problem  shall  work 
out,  time  only  can  decide.  With  it  once  worked  out, 
there  is  no  doubt  that  the  level  of  humanity  will  be 
distinctly  raised.  No  other  one  feature  in  the  pro- 
gram of  eugenics  seems  more  absolutely  hopeful  than 
this. 

In  several  of  the  states  of  the  Union  it  has  re- 
cently become  the  practice  to  remove  the  possibili- 
ties of  parenthood  from  certain  classes  of  criminals. 
The  purpose  of  this  is  clear  and  benevolent.  Society 
has  a  right  to  prevent  the  oncoming  of  new  genera- 
tions of  foreordained  criminals.  Underlying  the 
practice  is  the  theory  that  the  children  of  criminals 
are  born  criminals.  It  is  far  from  likely  that  this 
is  the  case.  Criminality  may  be  due  to  a  wide  range 
of  causes.  If  the  criminal  is  one  of  those  actual 
born  degenerates  whose  whole  mental  and  physical 
make-up  is  so  defective  that  nothing  but  criminality 
can  be  expected  of  him,  then  we  have  a  case  in  which 
it  is  clear  that  society  may,  and  should,  remove  the 
possibility  of  having  more  generations  of  the  same 
kind.  Probably  only  a  moderate  proportion  of  the 
criminals  in  our  jails  and  penitentiaries  belong  to 
this  class.  Doubtless  a  distinct  majority  are  crim- 
inals more  through  environment  than  through  hered- 
ity.    Born  of  average  ability,  or  more,  these  people 


268  THE    MEANING    OF    EVOLUTION 

have  been  criminals  simply  because  they  were  reared 
among-  criminals,  because  their  surroundings  were 
such  as  to  lead  them  away  from  habits  of  industry, 
while  they  must  live.  These  people  were  not  bol- 
stered by  society,  or  the  church,  into  a  life  of  self-re- 
spect and  self-help.  Under  these  circumstances  they 
fell  into  evil  ways.  There  is  nothing  defective  in 
their  mental  or  physical  makeup,  that  need  appear  in 
their  children.  If  these  children  are  removed  from 
contact  with  the  criminal  class  they  stand  every 
chance  of  being  as  vigorous,  as  intelligent,  as  upright 
as  the  average  of  the  community. 

At  the  recent  Eugenics  Congress  in  London  one  of 
the  speakers  expressed  a  preference  for  the  son  of  a 
husky  burglar  over  the  son  of  a  tuberculous  bishop. 
This  is  doubtless  quite  correct,  but  why  should  the 
bishop  be  tuberculous?  The  truth  of  the  matter  is, 
the  reverse  is  more  likely  to  be  the  case.  Personally, 
I  should  prefer  to  be  the  offspring  of  a  husky  bishop. 
In  dealing  with  criminals,  then,  with  a  view  to  cut- 
ting off  their  posterity,  we  must  be  careful  to  under- 
stand whether  we  are  dealing  with  a  hereditary  or 
an  acquired  criminality.  If  there  is  a  genuine  heredi- 
tary criminal  taint,  society  is  right  in  freeing  itself 
of  it.  If  it  is  acquired  criminality,  then  it  is  not 
transmissible,  and  the  offspring,  if  placed  in  a  good 
environment,  are  likely  to  be  good  citizens.     All  of 


THE    FUTURE    EVOLUTION    OF    MAN  269 

which  means  that,  until  we  are  clearly  sure  of  what 
constitutes  a  hereditary  criminal  trait,  we  should 
move  very  slowly  in  the  matter  of  mutilating  crim- 
inals. 

What  steps  may  the  eugenist,  with  his  present 
limited  knowledge,  clearly,  hopefully  and  confidently 
take  to  improve  the  future  of  the  human  species? 
There  is  one  avenue  open  to  us  in  this  matter  in 
which  we  can  hardly  go  wrong.  Even  our  mistakes 
can  work  little  harm,  and  every  well-done  piece  of 
work  in  this  field  will  be  a  blessing  to  the  race.  This 
step  lies  in  inculcating  in  our  boys  and  girls  high 
ideals  of  parenthood.  This  is  more  effective  than 
legal  prohibition  of  certain  forms  of  marriage  which 
cannot  prevent  matings,  ancf  adds  the  curse  of  illegiti- 
macy to  the  other  handicaps  of  the  children  of  such 
unions.  The  first  step  in  this  process  has  already 
been  reasonably  well  accomplished.  Both  our  boys 
and  our  girls  are  in  love  with  health.  A  good  hus- 
band and  a  good  wife  should  be  healthy  and  vigorous. 
This  does  not  mean  that  we  expect  a  boy  or  girl  who 
is  looking  forward  to  marriage  to  sit  down  and  ask 
himself  deliberately  about  the  health  of  the  person 
with  whom  he  would  mate.  We  must  fill  our  chil- 
dren with  the  love  of  outdoor  life,  with  the  love  of 
exercise.  This  will  foster  in  them  an  admiration  for 
people  who  are  vigorous  of  body  and  alert  of  mind. 


270  TTIE    MEANING    OF    EVOLUTION 

It  onght  to  become  practically  impossible  for  a 
hearty  and  vigorous  boy  to  fall  in  luve  with  a  help- 
less and  anaemic  girl.  It  should  be  ccjually  impossi- 
ble for  a  hale  and  active  girl  to  admire  a  man  who 
was  her  inferior  in  either  vigor  or  alertness.  The 
modern  taste  for  outdoor  life  has  largely  brought 
this  to  pass  among  such  of  our  people  as  have  leisure 
enough  to  indulge  in  vigorous  sport.  Among  the 
crowded  dwellers  in  the  closer  sections  of  the  city 
such  life  has  been  so  nearly  impossible  that  no  ideal 
of  vigorous  manhood  or  of  radiant  womanhood  has 
had  a  chance  to  grow  up.  With  the  oncoming  of  the 
parks  and  play-grounds,  all  of  this,  we  may  hope, 
\y\\\  change.  Health  and  vigor  w\\\  be  no  less  attain- 
able and  hence  no  less  adorable  in  the  city  than  in 
the  country.  Rich  and  poor  alike  will  be  attracted 
by  rosy  cheeks  and  an  elastic  gait. 

Our  aim,  however,  should  not  cease  with  a  vigor- 
ous body.  We  must  teach  our  young  men  and  young 
women  the  glory  of  a  well  disciplined  mind.  This 
should  seem  quite  as  admirable  to  them  as  a  vigorous 
body.  To  them,  straight  thought  ought  to  be  as  lov- 
able as  a  firm  and  supple  body.  In  this  matter  our 
young  people  are  less  exacting.  The  ordinary  con- 
versation of  people  gathered  together  for  social  pur- 
poses is  not  particularly  intellectual,  and  any  attempt 
to  make   it   so  at  present   seems  priggish.      W^ith  a 


THE    FUTURE    EVOLUTION    OF    MAN  27 1 

broader  education,  will  come  keener  demand  for  in- 
telligence. We  may  hope  the  time  is  not  too  far  dis- 
tant when  a  question  of  governmental  policy,  a  new 
book  or  play,  or  a  new  discovery  in  science  will 
stimulate  as  much  conversational  zest  as  now  seems 
to  be  gotten  from  a  pack  of  cards. 

A  third  feature  of  the  ideals  which  should  be  in- 
stilled into  the  minds  of  our  children  is  the  moral 
phase.  There  seems  little  doubt  that  this  is  on  the 
way.  We  must  not  mistake  an  evident  laxness  of 
religious  observance  as  being  synonomous  with  moral 
looseness.  The  revelations  which  our  recent  period- 
icals have  brought  us  concerning  the  habits  of  busi- 
ness men,  of  politicians,  and  of  society,  have  left 
on  many  minds  the  impression  that  this  is  distinctly 
an  age  of  decadence.  Exactly  the  reverse  is  the 
truth.  This  is  the  age  of  intense  sensitiveness  to 
wrong.  In  almost  no  particular  is  it  worse  than  any 
previous  age  in  the  history  of  our  country.  We 
openly  discuss  things  which  we  left  untouched  a  lit- 
tle while  ago.  We  insistently  demand  that  business 
practices  to  which  nobody  particularly  objected  a 
dozen  years  ago  must  now  certainly  cease.  All  of 
this  has  produced  an  erroneous  impression  that  the 
times  are  out  of  joint.  But  the  dust  and  dirt  in  the 
air  is  the  unavoidable  accompaniment  of  house  clean- 
ing.    When  doubtful  practices  simply  have  publicity 


272  THE   MEANING   OF   EVOLUTION 

many  arc  awakened  to  the  sense  of  their  duty  to  so- 
ciety. Persons  who,  of  themselves,  might  be  wilHng 
to  live  low  and  godless  lives,  dare  not  do  so  in  the 
face  of  society  when  our  social  ideals  are  finer.  I 
believe  there  is  the  utmost  hope  that  within  two  gen- 
erations our  young  men  and  young  women  will  scorn 
meannesses  which  we  are  accepting  with  entire  com- 
placency. 

A  close  acquaintance  with  thousands  of  young  men 
and  young  women  running  through  an  experience  of 
twenty-five  years  has  taught  me  to  believe  that  our 
young  people  of  to-day  are  altogether  cleaner  of 
mind,  of  tongue,  and  of  life  than  were  their  parents. 
There  is  freer,  franker  discussion  of  many  things 
that  their  parents  would  scarcely  have  dared  mention, 
yet  I  feel  sure  the  moral  tone  is  distinctly  higher. 
I  look  with  entire  hopefulness  to  an  early  season 
w^hen  the  young  man  who  asks  a  woman  to  share  her 
life  with  him  will  be  met  with  the  entirely  proper 
question,  ''Have  you  kept  your  life  clean  for  this 
event?"  I  believe  that  unless  the  answer  can  be  in  the 
affirmative  the  young  woman  will  not  be  able  to  have 
admiration  enough  for  the  young  man  to  cover  un- 
clcanness  in  his  life. 

There  is  one  temporary  phase  of  present  life  which 
seems  discouraging.  The  increase  in  the  cost  of  liv- 
ing, and  still  more  rapid  increase  in  the  standard  of 


THE   FUTURE   EVOLUTION    OF   MAN  273 

living  is  shifting  too  late  in  life  the  age  at  which 
our  young  people  marry.  The  result  is  that  one  of 
two  things  is  likely  to  happen;  either  a  large  number 
of  people  are  likely  not  to  marry  at  all,  or  the  ro- 
mantic time  of  life  is  passed  before  the  event  occurs 
which  it  is  intended  to  bless.  A  young  man  and 
young  woman  who  are  in  this  time  of  life  can  deny 
themselves  for  each  other,  can  struggle  and  plan 
together,  can  hope  and  trust  together  to  an  extent 
that  can  never  be  the  case  if  marriage  is  delayed  be- 
yond  the   romantic  years. 

The  best  foundation  possible  for  a  life  of  happi- 
ness is  vigor,  ability  and  good  character.  For  the 
lack  of  none  of  these  can  wealth  properly  atone. 

There  is  an  apparent  tendency  to  waken  to  the 
situation.  I  hope  it  will  come  soon  enough  for  our 
young  men  and  young  women  to  get  past  a  desire 
for  such  establishments  in  life  as  their  parents  already 
have.  With  this  difficulty  removed,  with  our  wide- 
spread education,  with  the  constant  diffusion  of  both 
information  and  ideals  from  our  periodical  press  I 
have  every  hope  that  the  evolution  of  a  new,  a  finer, 
and  more  vigorous  race,  will  come  with  a  rapidity 
which  nothing  that  the  past  has  done  would  lead  us 
to  expect. 


CHAPTER    XI 

Science  and  the  Book 

We  of  the  twentieth  century  have  an  overwhehii- 
ing  desire  to  be  up  to  the  times.  Nothing  but  the 
latest  news  on  any  subject  will  completely  satisfy. 
We  are  more  anxious  for  late  information  than  for 
accurate  information.  We  have  an  almost  uncon- 
querable feeling  that  if  it  is  late  it  must  be  accurate. 
All  of  us  are  sensitive  to  being  thought  behind  the 
times.  We  feel  that  no  stigma  can  be  more  invidious 
in  the  intellectual  world  than  the  stigma  of  being  out 
of  date.  This  pervades  the  masses  quite  as  strongly 
as  it  does  the  more  cultured  classes.  Under  these 
conditions  everybody  wants  to  know  the  latest  theory 
that  science  has  to  offer  concerning  anything  that 
can  be  brought  within  the  range  of  their  interests. 
As  a  result  everybody  would  like  to  know  about  evo- 
lution, were  it  not  for  the  fact  that  a  great  mass  of 
people  have  been  brought  to  believe  that  there  is 
something  inherently  irreligious  in  the  idea.  Our 
people  have  a  saving  sense  of  the  value  of  religion. 
Denominational  control   may  set  lightly  upon   them. 

274 


SCIENCE    AND    THE    BOOK  275 

Certain  long  revered  doctrines  may  have  little  prac- 
tical influence  upon  them.  Yet  inherently  they  all 
believe  in  religion,  and  most  of  them  believe  them- 
selves to  be  religious,  as  indeed  they  really  are. 

It  is  a  most  wholesome  tendency  which  leads  us 
to  esteem  religion  as  the  main  interest  in  life.  We 
must  feel  a  sense  of  shame  when  we  consciously 
permit  the  influences,  which  most  favorably  mold 
our  character,  to  weaken  their  hold  upon  our  lives. 
Certainly  in  our  time  religion  is  the  essential  agent 
by  which  character  is  molded.  Any  of  us  would  be 
foolishly  short-sighted  were  he  willing  to  weaken  the 
hold  of  religion  upon  his  life  for  the  sake  of  a  scien- 
tific theory,  the  truth  or  falsity  of  which  could  have 
but  little  practical  bearing  upon  his  conduct.  We 
must  hold  to  religion  at  all  hazards.  We  may,  when 
circumstances  so  suggest,  change  our  denominational 
allegiance.  We  may  and  often  do  interpret  our  faith 
quite  at  variance  with  the  ecclesiastical  body  with 
which  we  are  connected.  We  may  constantly  modify 
and  develop  our  beliefs.  But  it  is  a  pitiful  life  which 
has  lost  the  staying  and  strengthening  influence  of 
religion.  I  believe  this  conviction  is  deep-rooted  in 
the  minds  of  our  people  and  that  it  deserves  the  place 
it  holds. 

To  a  mind  thus  essentially  religious  the  announce- 
ments of  science  often  come  as  a  shock.     They  seem 


276  THE    MEANING    OF    EVOLUTION 

to  run  counter  to  our  deepest  convictions.  It  seems 
impossible  to  us  that  both  can  be  true.  Sometimes 
the  more  we  debate  the  questions  the  more  contra- 
dictory they  seem  to  become.  Every  good  mind 
needs  unity  in  itself.  No  clear  thinker  can  be  quite 
content  when  two  distinct  departments  of  thought  are 
at  sharp  variance  in  his  mind.  He  may  pursue  one 
of  two  courses.  He  may  hold  to  one  view  with  con- 
viction and  earnestness  and  look  upon  the  other 
as  essentially  false.  To  many  religious  people  all 
science  that  runs  counter  to  their  convictions  is  neces- 
sarily false.  They  label  it  pseudo-science  and  pass  it 
by.  If  the  word  pseudo-science  is  unknown  to  them, 
they  stiginatize  it  as  rationalistic,  or  still  worse  as 
materialistic  and  let  it  go  at  that. 

The  other  course  is  to  have  faith  both  in  religion  • 
and  in  science. 

Such  a  fair-minded  man  must  ask  himself,  what  is 
the  truth  in  the  matter?  If  the  scientific  fact  is  true 
it  is  to  be  believed.  It  may  run  counter  to  what  we 
have  believed  before.  It  may  seem  at  first  entirely 
incredible.  But  when  once  he  becomes  convinced  of 
its  truth  the  clear  thinker  must  not  only  accept  it, 
but  must  accept  all  legitimate  deductions  from  it.  If 
it  seems  true  to  us  we  must  believe  it.  Absolute 
demonstrable  truth,  except  in  the  simplest  of  matters 
is  almost  unattainable.     The  best  we  can  ordinarily 


SCIENCE   AND   THE    BOOK  27/1 

get  is  a  close  approach  to  certainty,  and  with  this  we 
must  be  content.  In  many  matters,  indeed  in  most 
matters,  we  must  trust  the  judgment  of  others  who 
are  better  trained  in  a  particular  line  of  thought. 

As  to  the  truth  of  geology  we  are  certainly  wise 
to  accept  for  the  present  the  facts  and  principles  com- 
monly accepted  by  competent  geologists.  In  biology, 
we  should  respect  the  concurrent  opinion  of  impor- 
tant biologists.  We  must  not  assume  that  a  few 
biologists  who  think  as  we  do  are  right  against  the 
biological  world,  or  that  a  few  geologists  who  think 
as  we  do  are  right  against  the  geological  world.  For 
theology,  we  had  better  go  to  the  educated  theo- 
logian. But  when  it  comes  to  reconciling  two  of 
these  and  to  catching  the  inherent  correspondence 
between  them,  it  is  often  likely  that  each  of  these 
groups  of  men  is  unable  to  see  clearly  the  view-point 
of  the  other.  Here  lies  our  freedom.  Here  we  must 
either  think  for  ourselves  or  think  with  those  wiser 
than  ourselves  whose  opinions  seem  to  us  to  ring  true 
and  to  focus  for  us  our  wavering  and  uncertain 
thought. 

Among  students  of  animals  and  plants  there  is 
no  longer  any  question  as  to  the  truth  of  evolution. 
That  the  animals  of  the  present  are  the  altered  ani- 
mals of  the  past,  that  the  plants  of  to-day  are  the 


278  THE    MEANING    OF    EVOLUTION 

modified  plants  of  yesterday,  that  civilized  man  of 
to-day  is  the  savage  of  yesterday  and  the  tree-dweller 
of  the  day  before,  is  no  longer  debatable  to  the  great 
mass  of  biologists.  To  older  men  hampered  by  the 
convictions  of  an  earlier  age  this  dictum  of  modern 
science  may  still  be  a  little  uncertain. 

The  working  biologists  of  the  world  have  no  doubt. 
They  differ  radically  as  to  what  brought  about  this 
change,  they  dispute  vigorously  as  to  the  rate  of 
change,  but  as  to  the  fact  of  the  change  there  is  no 
difference  of  opinion.  Under  these  conditions  the 
thinking  man  is  out  of  joint  wath  the  times  when  he 
sets  himself  against  the  idea  of  evolution.  He  may 
be  so  immersed  in  other  lines  as  to  be  indifferent  to 
the  problem;  but  w^hen  he  is  hostile  to  it,  he  marks 
himself  as  clearly  against  his  day.  Many  have  been 
against  their  day  and  have  been  right.  Very  great 
men  have  often  been  against  the  opinions  of  their 
times  and  have  come  to  be  leaders  of  the  world's 
later  thought.  But  ordinary  men  in  ordinary  times 
who  think  differently  on  a  special  subject  from  the 
specialists  of  the  times  are  not  very  likely  to  be  right. 
It  is  safe  for  most  of  us  to  accept  as  true  an  opinion  ' 
on  which  specialists  on  that  subject  agree.  It  seems 
clear  to  me  then  that  the  thinking  man  to-day  has  in 
the  matter  of  evolution  a  double  duty.  He  must 
become   reasonably  acquainted  with  the   theory   that 


SCIENCE   AND   THE    BOOK  279 

SO  largely  affects  all  present  knowledge,  and  he  must 
wrestle  with  the  theory  until  it  no  longer  hinders  the 
hold  of  religion  upon  his  life.  He  may  be  perfectly 
sure  that  he  does  not  clearly  understand  both,  but 
he  must  get  them  into  reasonable  concordance  before 
he  can  be  quite  at  peace. 

Truth  is  true  no  matter  how  it  is  acquired.  There 
can  be  no  doubt  as  to  the  essential  truth  of  religion: 
its  fruits  proclaim  its  worth.  There  can  be  no  doubt 
as  to  the  essential  truth  of  evolution;  the  clarity  it 
has  brought  into  the  sciences  is  the  evidence  of  the 
value  of  the  conception.  That  it  will  persist  in  its 
present  form,  that  it  will  be  unchanged  by  later  ad- 
ditions to  our  knowledge  is  of  course  unthinkable.  It 
may  be  incomplete,  it  may  be  undeveloped,  but  so  far 
as  it  goes  it  contains  the  truth.  Under  these  condi- 
tions, how  can  we  bring  peace  into  our  own  mind? 
These  two  important  provinces  seem  so  often  to  be 
at  variance.  The  difficulty  may  lie  in  one  of  two 
places.  In  the  first  place,  each  truth  may  be  stated 
in  terms  so  peculiar  to  its  own  subject  as  to  convey 
no  meaning  to  the  student  of  the  other  branch.  There 
is  a  second,  and  more  harassing  possibility.  The 
same  words  may  be  used  by  students  in  each  branch 
but  each  side  may  put  a  different  significance  into  the 
terms.  Then  each  believes  he  understands  the  other, 
when  he  really  does  not. 


28o  TTIE    MEANING   OF   EVOLUTION 

Onr  tlicology  is  man's  interpretation  of  God's  reve- 
lations of  Himself  as  recorded  in  the  Bible.  Our 
science  is  man's  interpretation  of  God's  revelation  of 
Himself  in  nature.  Each  is  God's  revelation,  and  so 
far  as  we  have  understood  it,  that  revelation  is  of 
the  utmost  importance  in  our  lives.  Each  has  all 
the  inherent  short-comings  of  man's  interpretation. 
Each  has  all  the  difficulties  necessarily  found  in 
any  stage  of  a  developing  understanding.  We  may 
be  sure  if  we  could  thoroughly  understand  God's 
revelation  of  Himself  as  recorded  in  the  Bible  and 
his  revelation  of  Himself  as  recorded  in  the  rocks 
and  the  tissues  of  animals  as  well  as  in  the  body 
and  mind  of  man  to-day,  there  would  be  no  diffi- 
culty. When  we  understand  both  completely,  as  per- 
haps we  never  shall,  there  will  be  no  contradictions 
of  any  kind  between  them.  Even  now  if  we  are 
firmly  convinced  that  truth  must  be  in  both,  there 
will  be  little  difficulty  in  reaching  a  workable  unity 
which  will  satisfy  the  present  needs  of  the  human 
mind  and  will  not  be  so  crystallized  as  to  prevent  a 
future  growth.  H,  however,  we  hope  to  find  a  unity 
between  a  belief  in  evolution  and  a  belief  in  the  in- 
spiration and  value  of  the  Bible,  we  must  accept  both 
of  these  in  the  terms  of  to-day.  To  reconcile  a 
twentieth  century  statement  of  science  with  an  eigh- 
teenth  century   statement   of   theology   would   be   as 


SCIENCE   AND   THE   BOOK  281 

absurd  as  it  would  be  to  reconcile  a  statement  of 
twentieth  century  theology  with  eighteenth  century 
science.  Each  century  must  restate  its  truths  in 
terms  of  its  own  time.  The  truths  may  be  at  bottom 
the  same  through  many  centuries  but  to  be  clearly  in- 
telligible in  any  century  they  must  be  couched  in  the 
terminology  of  the  age. 

C  It  seems  to  me  if  we  are  to  understand,  in  con- 
formity with  the  thought  of  the  age,  any  particular 
book  in  the  Bible,  there  are  three  steps  through  which 
we  must  pass.  We  must  first  ask  ourselves  the  kind  . 
of  people  to  whom  the  book  vv^as  originally  written.  V 
We  must  know  their  habits  of  life  and  of  thought. 
Until  this  is  clear  in  our  minds  the  book  can  have 
little  significance.  Having  built  up  as  nearly  as  may 
be  the  life  and  thought  of  the  time,  we  must  next 
decide  what  is  the  inherent  truth  taught  to  the  people 
of  that  time  by  the  book  under  consideration.  Much 
that  is  written  must  be  simply  the  setting  in  which 
alone  that  truth  could  reach  them.  This  extraneous 
detail  gives  vigor  and  color  to  the  message  but  is 
not  the  message  itself.  The  last  step  and  the  hardest 
one  to  take,  the  one  that  to  some  minds  seems  almost 
irreverent,  is  to  decide  the  form  that  message  must 
take  to-day  to  convey  to  our  minds  the  same  truth 
which  the  original  message  conveyed  to  the  people  of 
its  time.     In  so  far  as  we  succeed  in  taking  these   J 


282  THE    MEANING    OF    EVOLUTION 

three  steps,  wc  shall  get  the  true  message  which  this 
book  holds  for  us  to-day. 

When  Paul  in  his  first  burning  letter  told  the  Cor- 
inthian congregation  that  their  women  should  be 
silent  in  their  churches,  he  is  not,  it  seems  to  me,  giv- 
ing a  message  which  in  those  terms  applies  to  the 
world  to-day.  If  a  woman  has  anything  that  is 
worth  saying  she  has  a  perfect  right  to  say  it  in 
church.  In  any  denomination  in  which  religious  ob- 
servance is  not  ecclesiastically  formal  she  will  be  al- 
lowed that  privilege.  By  an  interesting  peculiarity 
of  mind  on  our  part  she  may  be  permitted  to  do  so 
upon  Wednesday  evenings,  when  our  early  prejudice 
still  prevents  her  speaking  on  Sunday.  What  is  the 
truth  of  the  teaching  of  Paul  in  this  matter?  The 
Christians  of  Corinthian  times  had  already  begun  to 
suffer  from  persecution.  They  w^re  already  despised 
and  distrusted.  Men  had  come  to  speak  ill  of  them. 
Paul's  injunction  concerning  the  silence  of  women  in 
churches  was  simply  an  injunction  against  their  doing 
those  things  which  in  the  thought  and  habit  of  those 
times  were  associated  generally  with  looseness  of 
character.  Fine  Corinthian  women  did  not  speak  in 
public.  A  woman  who  would  consent  to  speak  before 
a  group  of  men  of  Corinth  of  that  day  would  by  that 
fact  have  proclaimed  herself  a  woman  of  loose  mor- 
als.    Paul's  injunction  is  that,  in  this  desperate  strug- 


SCIENCE    AND    TPIE    BOOK  283 

gle  Christian  women  should  do  nothing  which  could 
possibly  bring  them  into  disrepute.  The  lives  of 
Christians  must  be  above  suspicion.  This  message 
is  certainly  as  true  to-day  as  it  was  in  the  time  of 
Paul  and  Corinth.  Whether  or  not  a  woman  speaks 
in  church  to-day  has  no  bearing  whatever  upon  the 
question.  The  question  is  how  she  speaks  and  what 
she  says.  If  her  life  gives  force  to  her  message  and 
her  message  contains  God's  truth  she  is  entirely  free 
to  speak. 

In  similar  fashion  we  have  changed  most  beauti- 
fully the  message  which  we  have  come  to  love,  as 
the  Mizpah  message :  "The  Lord  watch  between  thee 
and  me  while  we  are  absent  one  from  the  other." 
We  have  absolutely  transformed  and  glorified  the 
message.  It  was  once  the  calling  down  of  the  wrath 
of  Jehovah  upon  one  or  other  of  two  herdsmen  if 
either  of  them  should  fail  to  comply  with  the  agree- 
ment to  remain  within  his  own  boundary.  These 
men  whose  herdsmen  were  constantly  stealing  each 
other's  cattle  agreed  to  separate  because  they  could 
not  live  in  unity.  They,  set  up  a  heap  of  unhewn 
stone,  and  called  upon  God  to  guard  and  to  see  that 
neither  of  them  passed  beyond  the  boundary  of  the 
other.  What  was  once  a  threat  between  warring 
herdsmen  has  become  a  binding  link  between  Chris- 
tian brothers.     No  longer  do  vve  call  upon  the  Lord 


284  THE    MEANING   OF   EVOLUTION 

to  guard  in  our  absence  lest  our  enemy  encroach  upon 
our  domain.  Now  we  call  upon  him  to  bind  our 
hearts  together  so  that  neither  time  nor  circumstance 
can  bring  division  between  us.  The  menace  of  a 
herdsman's  wrath  has  become  one  of  the  tenderest 
messages  of  Christian  love. 

In  the  light  of  the  principles  stated  above,  what 
is  the  essential  truth  that  lies  back  of  the  earliest  chap- 
ters of  Genesis?  First,  that  there  is  one  God.  Slowly 
it  had  been  borne  in  upon  the  Hebrew  mind  as  upon 
no  other  tribe  in  the  world  that  the  Lord  God  is  one 
God.  Nearly  all  the  world  besides  believed  in  many 
gods.  Each  nation  had  a  God  peculiarly  its  own, 
each  city  had  a  minor  god  caring  for  it  particularly. 
There  were  gods  of  the  woods,  gods  of  the  oceans, 
gods  of  the  streams.  Gods  and  goddesses  were  every- 
where. To  this  people  wandering  through  the  terri- 
ble monotony  of  the  sandy  desert,  the  "Garden  of  Al- 
lah," there  came  the  inspired  comprehension  of  the 
eternal  oneness  of  Almighty  God.  First,  he  was  to 
most  of  them  the  God  of  the  Hebrew,  stronger  than 
the  gods  of  the  nations.  After  a  while  under  the 
teaching  of  prophet  after  prophet  there  finally  came 
to  the  entire  nation  the  exalted  conception  that  God 
is  one  and  there  is  no  other  God.  This  is  one  of  the 
imperishable  revelations  of  all  time.  Beside  this,  all 
suggestions  of  fifth  or  sixth  day,  of  hours  or  of  ages 


SCIENCE   AND   THE   BOOK  285 

are  absolutely  insignificant.  These  are  but  the  cloth- 
ing of  the  idea  which  makes  it  acceptable  to  its  time. 
This  clothing  must  change  with  every  age  if  it  would 
reach  thoroughly  the  minds  of  the  age.  Underneath 
and  forever  lies  the  glorious  truth  that  the  Lord  God 
is  one  God. 

The  second  truth  which  seems  to  me  to  underlie  this 
magnificent  parable  of  creation  is  the  truth  that  this 
great  God  has  created  the  universe  and  that  he  cares 
for  his  people.  Gods  before  had  been  objects  of  ter- 
ror. Gods  before  had  lived  lives  such  as  the  people 
themselves  would  not  have  respected  among  their 
companions.  Gods  before  were  to  be  vshunned.  If 
one  could  but  escape  the  attention  of  the  gods  it  was 
his  greatest  good  fortune.  Now  we  have  the  concep- 
tion of  an  all-knowing,  ever-present  God  to  whom  his 
people  are  dear.  The  terms  in  which  it  was  stated  In 
those  days  matter  but  little.  To  modern  psychologists 
even  the  idea  that  people  are  dear  to  God  seems  speak- 
ing too  humanly.  Yet  the  truth  involved  must  come 
in  terms  that  the  people  of  to-day  understand.  We  can 
best  comprehend  God  if  we  think  of  Him  as  loving 
and  chastening,  even  though  down  in  our  hearts  we 
know  that  these  terms  are  not  high  enough,  are  too 
human  to  apply  to  an  Eternal  God.  But  we  know  no 
better  and  they  tell  us  the  truth  even  though  the  terms 
may  in  time  pass  completely  away. 


286  THE    MEANING    OF    EVOLUTION 

Last  of  all  and  perhaps  most  characteristic  of  the 
Hebrew  people  is  the  great  lesson  that  this  Eternal 
God,  who  created  the  universe  and  cares  for  his 
people,  demands  righteousness  of  his  people.  To  the 
nations  round  about  religion  was  not  a  matter  of 
righteousness.  For  them  religion  had  nothing  to  do 
with  morality.  Thieves  might  have  gods  favorable 
to  them  quite  as  well  as  righteous  men.  The  worship 
of  Diana  of  the  Ephesians  or  of  Astarte  in  the  groves 
of  the  Asia  Minor  coast  could  be  so  unspeakably  licen- 
tious and  vile  as  not  to  admit  of  description  to-day. 
Yet  this  was  all  religion.  To  the  Hebrew  came  the 
inspired,  exalted  conception  of  a  God  who  demanded 
righteousness  of  his  people.  Beside  this  wonderful 
revelation  to  the  human  mind  details  of  serpents,  and 
of  apples,  of  names  of  men  and  of  women,  of  gardens 
and  of  swords  are  absolutely  but  the  transitory  cloth- 
ing. This  brought  them  to  the  minds  of  the  times. 
The  value  of  the  form  is  evidenced  by  the  fact  that  it 
brought  the  conception.  But  we  must  not  lose  the 
glory  of  the  conception  in  an  over  regard  for  the 
clothing  in  which  the  idea  came. 

Does  this  mean  that  Genesis  has  served  its  purpose 
and  is  to-day  to  be  conceived  of  as  a  beautiful  relic  of 
the  past,  to  be  reverently  enshrined  but  not  seriously 
accepted?  Far  from  it.  The  glory  of  the  Genesis 
story  lies  in  its  wonderful  power  to  grow.    It  strength- 


SCIENCE    AND   THE    BOOK  28/ 

ened  the  minds  of  a  persecuted  tribe  wandering  in  the 
desert  who  finally  settled  in  a  small  and  barren  coun- 
try. It  brought  the  truth  to  them  so  clearly  that  they 
have  persuaded  much  of  the  world  of  that  truth  and 
bid  fair  to  persuade  the  rest.  The  story  has  grown 
with  the  mind  of  man.  As  it  served  the  Hebrew  in  his 
time  it  has  grown  to  serve  others  to  this  day.  Each 
generation  has  read  the  story  in  the  light  of  its  own 
times  and  each  generation  w^ill  continue  to  read  the 
story  in  the  light  of  its  advancing  knowledge.  The 
only  part  of  the  story  that  can  be  affected  is  the 
clothing,  the  inherent  truth  remains  forever,  further- 
more, the  story  which  persuaded  the  childhood  of 
race  is  the  story  which  will  persuade  the  childhood 
of  to-day.  In  no  other  form  could  the  great  truth  of 
the  Bible  be  brought  to  our  children  as  well  as  in 
the  form  of  these  early  chapters.  In  early  life  our 
children  will  accept  these  stories  as  literally  as  the 
ancient  Hebrew  accepted  them.  As  they  grow  in 
knowledge,  unconsciously  and  without  jar,  if  we  do 
not  jar  them,  our  children  will  read  into  the  story 
what  God  has  taught  them  in  the  world  outside.  The 
shock  which  came  to  their  elders  need  never  come  to 
them.  It  is  our  fault  if  our  children  are  disturbed 
by  the  conflict  between  religion  and  science  which 
disturbed  us.  There  is  no  difference  between  God's 
revelation  of  Himself,  as  we  have  it  in  the  Bible,  and 


288  THE    MEANING    OF    EVOLUTION 

God's  revelation  of  Himself  in  nature.  The  better 
we  know  the  Bible  and  the  better  we  know  nature 
the  clearer  this  will  be  to  us. 

Perhaps  the  most  severe  shock  that  has  come  to 
the  mind  of  religious  man  from  the  teachings  of 
science  has  been  the  at  first  almost  unsupportable 
idea  that  man  is  the  descendant  of  creatures  of  which 
the  ape  is  to-day  the  nearest  representative.  He  had 
learned  from  Genesis  the  altogether  adorable  con- 
ception that  he  was  made  in  the  image  of  his  Maker. 
It  lifted  him;  it  strengthened  him;  it  gave  him  more 
power  to  struggle.  He  might  know  that  he  had 
marred  that  likeness  by  wrong-doing,  he  might  un- 
derstand that  the  fulness  of  the  glory  of  God's  image 
could  not  shine  through  his  own  face.  Yet  he  be- 
lieved that  he  was,  in  spite  of  all  his  imperfections, 
made  in  the  image  of  his  Maker.  Now  comes  this 
horrible  linkage  with  a  miserable  brute  to  either  shock 
and  confound  him  or  to  degrade  him.  We  can  easily 
,  imagine,  some  of  us  have  bitterly  experienced,  the 
shock  of  this  changed  conception.  But  it  was  only 
because  we  mistook  the  clothing  for  the  truth  in  both 
cases.  We  read  science  in  its  own  terms;  we  read 
Genesis  in  its  own  terms.  They  did  not  use  the 
same  language  and  they  jarred  us  to  the  very  soul. 
Slowly,  however,  we  are  coming  out  of  the  darkness 
of  that  battle;  slowly  the  glorious  light  of  the  beauti- 


SCIENCE    AND   THE    BOOK  289 

ful  truth  is  breaking  into  our  minds  and  our  hearts. 

Michael  Angelo  painted  a  wonderful  picture  of 
'The  Judgment."  Here,  seated  upon  a  throne,  which 
after  all  is  only  a  magnificent  chair,  sits  a  venerable 
figure  of  what  is  really  but  a  nobly-proportioned 
man,  to  whom  the  nations  come  for  their  final  re- 
ward. He  separates  the  righteous  from  those  who 
must  forever  be  sundered  from  their  God.  Seen 
through  the  distant  past  it  still  remains  a  majestic 
picture;  but  no  painter  would  think  of  repeating  its 
conception  to-day. 

Quite  in  the  modern  spirit  is  the  beautiful  lunette 
which  John  Sargent  placed  in  the  Boston  Library, 
above  his  well  known  frieze  of  'The  Prophets."  It 
represents  "Jehovah  confounding  the  gods  of  the 
nations."  The  naked  figure  of  suppliant  Israel  stands 
before  an  altar  of  unhewn  stones,  on  which  burns 
the  sacrifice.  The  smoke  ascends  to  Heaven.  On  one 
side  stands  the  mighty  figure  of  Assyria  with  up- 
lifted mace  ready  to  strike  its  awful  blow  upon  the 
shoulders  of  helpless  Israel.  On  the  other  side  the 
lithe,  subtle  form  of  Egypt,  clasping  the  knout, 
watches  its  chance  to  bring  its  treacherous  thong 
upon  the  helpless  shoulders  of  suffering  Israel.  But 
Jehovah  may  not  appear,  man  may  not  look  on  God 
and  live.  Jehovah  is  seen  as  a  glory  behind  the  cloud 
of  smoke  shrouded  by  winged  cherubim.     From  one 


290  THE    MEANING    OF   EVOLUTION 

side  of  the  cloud  comes  a  mighty  hand  meeting  with 
power  the  force  of  Assyria.  From  the  other  side,  a 
Hthe  and  sinewy  hand  thwarts  the  subtlety  of  Egypt. 
But  Jehovah  is  behind  the  cloud. 

Again  we  understand  that  we  are  made  in  the 
image  of  our  Maker,  Again  we  understand  the 
power  of  the  uplift  of  this  idea.  From  the  conflict 
it  has  emerged  in  new  and  glorified  form.  Hath  a 
God  eyes  that  he  may  see?  Hath  a  God  ears  that  he 
may  hear?  Hath  a  God  hands  that  he  may  work? 
These  we  know  to  be  but  human  forms  of  speaking. 
Eyes,  ears,  and  hands  we  may  owe  to  the  brute  from 
whom  we  have  sprung;  in  our  eyes  and  ears  and 
hands  we  show  the  relationship  we  bear  to  them. 
These  are  not  the  image  of  God.  God  is  a  deeper,  a 
finer,  a  nobler  something  than  hands,  than  ears  and 
eyes.  The  image  of  God  lies  within  ourselves:  the 
image  of  God  is  that  which  makes  us  what  we  are. 
(In  every  noble  purpose,  in  every  earnest  endeavor  to 
uplift  ourselves  or  our  fellowman,  in  every  thought 
that  turns  us  from  the  evil  of  a  repented  past,  in  every 
desire  with  which  our  hearts  yearn  to  strengthen, 
support  and  sustain  our  friends  and  even  our  ene- 
mies, shines  forth  the  image  of  Almighty  God.^  This 
it  is  that  links  us  with  the  Eternal :  this  it  is  that 
makes  it  worth  while  that  we  should  be  Eternal.  Be- 
sides this  what  are  hands  and  ears  and  eyes?     We 


SCIENCE    AND   THE    BOOK  29 1 

are  made,  all  in  us  that  is  noblest  and  highest,  in  the 
image  of  our  Maker. 

A  word  in  closing.  The  time  is  ripe  for  a  broader 
conception  of  theology  and  of  science  on  the  part  of 
those  who  are  not  trained  to  be  specialists  in  either. 
We  are  becoming  more  and  more  inherently  religious. 
We  are  becoming  more  and  more  enamored  of  the 
truth  in  all  its  forms.  The  times  are  ripe  for  us  to 
cease  the  struggle  and  to  strive  for  peace.  So  long 
as  men  insist  that  the  important  things  in  faith  are 
the  things  on  which  men  differ  there  will  be  eternal 
strife.  So  soon  as  men  endeavor  to  find  the  common 
ground  between  them  and  each  tries  to  state  his  be- 
lief in  forms  acceptable  to  himself  but  involving  no 
hostility  to  his  neighbor,  we  shall  be  working  for 
peace. 

Some  of  our  finest  men  of  to-day  are  being  trained 
in  modern  science  and  in  modern  theology.  There 
is  no  scorn  in  their  minds  for  early  science  or  for 
early  theology.  Each  served  its  age,  and  each 
taught  its  truth.  But  its  truth  must  be  restated  in 
terms  of  to-day.  The  old  creeds  will  always  be  loved. 
The  old  creeds  will  always  hold  our  reverence  and 
allegiance.  But  each  age  must  be  at  liberty  to  in- 
terpret these  creeds  in  the  terms  in  which  that  age 
best  understands  truth.  Each  age  must  be  at  lib- 
erty *'to  restate  the  doctrines  of  the  past  in  accordance 


292  THE    MEANING    OF    EVOLUTION 

witli  the  newness  of  the  age  and  with  the  ancient 
verity  of  truth."  How  feeble  my  own  attempt  is  in 
this  matter,  I  quite  understand;  I  am  still  a  child  of 
the  struggle.  It  has  all  come  in  my  lifetime  and  I 
have  seen  and  felt  not  a  little  of  the  bitterness  of  it. 
I  believe  the  time  is  ripe  for  a  definite  peace.  I  be- 
lieve our  children,  if  we  do  not  hamper  them,  will 
never  know  the  struggle  we  have  had.  In  every 
great  institution  throughout  this  broad  land  men  of 
earnest  mind  and  noble  soul  are  teaching  the  truth 
as  God  gives  it  to  them  to  know  the  truth.  Let  us 
not  hesitate  to  entrust  our  children  to  their  hands. 
To  us  they  may  seem  to  be  teachers  of  discord  but 
they  are  not  speaking  in  terms  that  we  understand. 
They  are  using  the  language  of  a  new  age.  Under- 
neath their  teaching  lies  the  everlasting  truth.  Out 
of  their  teaching  will  come  everlasting  life.  Let  us 
trust  God  in  the  world.  Let  us  believe  that  in  this 
age  he  is  teaching  men's  lips  and  dwelling  in  men's 
hearts.  Only  so  can  we  give  to  our  children  the 
best  their  times  can  give  them.  If  we  insist  in  hold- 
ing these  men  back  to  our  conception  we  but  deny 
them  the  privilege  of  moving  with  God's  great  pro- 
cession. We  make  them  laggards  when  they  should 
be  in  the  front  ranks,  their  faces  lighted  by  a  nearer 
and  clearer  vision  of  Almighty  truth. 


INDEX 


Acquired  characters  not  inher- 
ited, 52. 
Adaptation  and  purpose,  89. 
Adaptation  for  the  individual, 

87. 
Adaptation  for  the  species,  125. 

Advanced  teaching,  291. 

Agassiz  and  evolution,  19. 

Age  of  the  earth,  156. 

Allantois  of  chick,  206. 

American  Museum  of  Natural 
History,  221. 

Anaxagoras  and  evolution,  9. 

Anaximander  and  evolution,  8. 

Ancestry  of  man,  186. 

Andes  rising  out  of  Pacific,  32. 

Aquinas,  Thomas,  and  evolu- 
tion, 12. 

Archseopteryx,  181. 

Aristotle   and   evolution,   9. 

Armadillo  and  glyptodon,  29. 

Artificial  flavors,  161. 

Artificial  proteids,  161. 

Artificial  sugars,  161. 

Ascent  of  man,  189. 

Asexual  reproduction,  194. 

Augustine,  Saint,  and  evolu- 
tion, II. 

Australian  mammals,  186. 


B 

Bank  swallow's  nest,  146. 


Barnacles    studies   by    Darwin, 

34. 
Beagle    and    Darwin's    voyage, 

25. 
Beauty  of  human  female,  127. 
Biologists  accept  evolution,  278. 
Bird  colors,  131. 
Bird  from  reptile,  122. 
Bird  nests,  145. 
Birds  of  a  region  definite,  61. 
Bird  song,  135. 
Blowing  viper,  107. 
Blue  birds  and  frost,  61. 
Bradbury,  Dean,  43. 
Buffon  and  evolution,  15. 
Bumble  bees,  125. 
Butterfly  colors,  129. 
Butterfly's  mouth,  95. 


Carboniferous  age,  174. 
Carnivorous  teeth,  124. 
Caterpillars  on  leaves,  no. 
Cave  man,  188. 
Cells  live  in  water,  166. 
Cenozoic  age,  185. 
Cicada  killer,  143. 
Circular  nest  of  bird,  147. 
City  life  in  man,  256. 
Clothing  of  birds,  loi. 
Coal  plants,  174. 
Cold-blooded  animals,  99. 
Color,  concealing,  Thayer,  115. 
Concealing  appearance,  105. 


293 


294 


INDEX 


Cope  and  Lamarckianism,  244. 
Cope  on  taste  of  toad,  118. 
Coral  reef  formation,  32. 
Country  life  in  man,  256. 
Cretaceous   period,   180. 
Cricket  song,   134. 
Crinoids,  171. 

Crossing  and  variation,  53. 
Cuvier  criticises  Lamarck,  19. 


D 


Darwin,  Charles, 

along  La  Plata,  28. 

at  Buenos  Ayres,  28. 

at  Keeling  Atoll,  31. 

at  Galapagos,  30. 

father  of  evolution,  21. 

in  Brazil,  27. 

in  Patagonia,  29. 

in  Peru,  30, 

on  Beagle,  26. 

persuaded    world    of    evolu- 
tion, 21. 

studies  Lyell's  Geology,  26. 

studies  Malthus,  35, 
Darwin,    Erasmus,    and    evolu- 
tion, 16. 
Darwin's  ancestry,  22. 

birth,  23. 

burial  in  Abbey,  43. 

death,  43. 

education,  23. 

narrative  of  voyage,  33. 

patient  mind,  45. 

purity  of  mind,  29. 

return  to  England,  33. 

short  sketches,  39. 

study  of  barnacles,  34. 

work  double,  233. 


Deer  horns,    138. 
Descartes  and  evolution,  12. 
Descent  of  man,  189. 
Determinants  in  nucleus,  238. 
Development  of  chick,  204. 
Development  of  pond-snai  s,  46. 
Devonian  age,  173. 
Devonian  fish,  173. 
DeVries  and  mutation,  246. 
Duckmole,  208. 


Early  marriage,  272. 
Earth's  age,  155. 
Ecstatic  flight,  136. 
Egg-laying  mammals,  208. 
Eimer  and  orthogenesis,  243. 
Elements  of  Geology,  Lyell,  26. 
Emanuel   Kant   and   evolution, 

13. 

Embryo  of  chick,  203. 

Emerson  and  nature,  48. 

Empedocles  and  evolution,  8. 

English  sparrow  (see  Sparrow, 
English). 

Environment  in  man,  258. 

Eugenic  program,  269. 

Evening  primrose  and  muta- 
tion, 246. 

Evolution  since  Darwin,  233. 


Feeble-mindedness,  264. 
Feet  of  mammals,  122. 
First  living  things,  165. 
Fish  eggs,  145. 
Fish  may  freeze,  104. 
Fitz-Roy,  Capt.,  and  Beagle,  25, 
Freedom  of  teaching,  291. 


INDEX 


295 


Fright   paralysis,   108. 

Frog'f  long  tadpole  stage,  112. 

Frost  and  bluebirds,  61. 

Fur  of  seal,  100. 

Futuifc  evolution  of  man,  249. 


Galapagos   Islands   and   evolu- 

t'on,  30. 
Geological  periods,  158. 
Glyptodon  and  armadillo,  29. 
Gnethe  and  evolution,  20. 
Graphite  from  plants,  168, 
Grasshopper's  mouth,  93. 
Grasshopper  song,  133. 
Groundhog  and  winter,  103. 
Growth  of  North  America,  167. 

H 

Haeckel  advocates  evolution, 
42. 

Health  certificates,  263. 

Henslow  and  Darwin's  educa- 
tion, 24. 

Henslow  suggests  Darwin  for 
Beagle,  24. 

Heredity  and  natural  selection, 

45- 
Heredity  in  man,  258. 
Homes,  few  animals  have,  98. 
Homes,  warm-blooded  animals, 

lOI. 

Horn  of  rhinoceros,  123. 
Horns  of  deer,  138. 
Horse  and  early  man,  232. 

earliest,  223. 

neck,  229. 

story  of  J  220. 

three-toed,  227. 


Horseshoe  crab,   171. 

How  mammals  developed,  192. 

Huxley  at  Oxford  meeting,  42. 


Ichneumon  fly,  142. 
Image  of  God,  288. 
Improving     the     environment, 

259. 

Improving  the  stock,  261. 

Inheritance  of  acquired  charac- 
ters, 238. 

Insect's  biting  mouth,  93. 

Interpretation  of   Genesis,  284. 

Isolation,  Jordan,  242. 

Isolation,  Romanes,  242. 

Isolation,  Wagner,  241. 


Java  skull,  187. 

Jehovah    confounding    the    na- 
tions, 289. 
Jordan  and  isolation,  242. 
Judgment,  Michael  Angelo,  289. 
Jukes  family,  265. 
June-bug,  107. 

K 

KalHkak  family,  265. 
Kant  and  evolution,  13. 
Katydid's  color,  iii. 
Katydid's  song,  133. 
Keeling  Atoll  and  Darwin,  31. 
King  Crab,  171. 


Lamarck  and  evolution,  17. 
Lampshells,  172, 


296 


INDEX 


LaPlacc's  theory,  151. 
Leibnitz,  and  evolution,  13. 
Life  from  other  planets,  162. 
Life  in  the  past,  149. 
Life,  its  nature,  247. 
Linnaean  Society  and  evolution, 

40. 
Linnceus  and  fixed  species,  15. 
Locust's  song,  135. 
Lucretius   and   evolution,   10. 
Lung-fish,   176. 
Lyell's  Geology,  26. 


M 


Male  birds  brighter,  131. 
Male  insects  sing,  134. 
Malthus  and  population,  35, 
Mamma,  significance  of,  211. 
Mammals,  egg-laying,  208. 

how  developed,  192. 
Man  and  God's  image,  288. 

early,  and  horse,  232. 

growing  better,  255. 
Man's  ancestry,  250. 

future  evolution,  249. 
Mating  and  song,  133. 
Mating  antics,   136. 
Meaning  of  Genesis,  284. 
Megatherium  and  sloth,  29. 
Mesozoic  age,  178. 
Michael      Angelo,      Judgment, 

289. 
Migration  of  birds,  103. 
Missing  link,  187. 
Miz-pah,  283. 
Modern    teachers    of    biology, 

291. 
Mongolian  idiot,  26$. 


Mosquito's  bite,  97. 
Mosquito's  mouth,  96. 
Mother-love,  217. 
Multiplication     and     evolution, 

54. 
Mutation  and  DeVries,  246. 


N 


Nature  of  life,  247. 
Nature  of  milk,  214. 
Natural  selection  explained,  45. 

in  brief,  36. 
Nebular  hypothesis,  152. 
Neck  of  horse,  229. 
Neo-Darwinians,  237. 
Nests  for  warm  eggs,  loi. 
Number       and       position       of 
breasts,  215. 


O 


Odor  as  protection,  117. 
Opossum  playing  dead,  107. 
Origin  of  birds,  181. 

feathers,  102. 

flightj  122. 

hair,  102. 

life,  159. 

lungs,  177. 

milk  glands,  212. 

placenta,  210. 

variations,  50- 
"Origin  of  Species"  published, 

41. 
Orthogenesis  and  Eimer,  243. 

Oxford  meeting  of  British  As- 
sociation, 41. 


INDEX 


297 


Palaeozoic  era,  170. 

Paley's  Natural  Theology,  87. 

Pangenesis,  236. 

Patagonia  and  its  terraces,  29. 

Phenacodus,  185. 

Physical  evolution  of  man,  254. 

Pithecanthropus,  188. 

Planetesimal  theory,  155. 

Playing  dead,   107. 

Playing  'possum,  107. 

Polygamy  in  animals,  137. 

Pond-snail,  development  of,  46. 

Potato  w^orm,  142. 

Protective  coloration,  109. 

Protoplasm,   164. 

Pterodactyl,    180. 

Puff  adder,  107. 

Purpose  and  adaptation,  89. 

Purpose  in  nature,  88. 

Q 

Quiet  and  escape,  105. 


R 


Raining  toads,   113. 
Religion  and  evolution,  74. 
Reptiles  of  Mesozoic,  179. 
Reproduction,  asexual  and  sex- 
ual, 194. 

in  fisheSj  196. 

in  frogs,  199. 

in  reptiles,  202. 
Rhinoceros  horn,  123. 
Romanes  and  isolation,  242. 
Rooster  finer  than  hen,  132. 


Saint  Augustine  and  evolution, 

II. 
Salamanders,  176. 
Sargent's  picture,  289. 
Science  and  the  book,  274. 
Science  and  theology,  280. 
Science,  definition,  280. 
Seals  and  polygamy,  139. 
Sealskin  and  fur,  100. 
Sedgwick  and  Darwin,  24. 
Selection  and  evolution,  56. 
Sexual  selection,  126,  128. 
Skunk's  odor,  117. 
Sloth  and  megatherium,  29. 
Song  and  mating,  133. 
Sparrow,    English,   adapted   to 
town,  66. 

and  hawks,  69. 

and  winter,  "j^t- 

eat  varied  food,  71. 

eye-minded,  78. 

feed  young  on  insects,  ^2. 

good  qualities,  85. 

has  reached  limit,  85. 

in  Philadelphia,  63. 

introduction,  62. 

lives  near  houses,  70. 

nests  early,  81. 

nests  often,  82. 

once  migratory,  80. 

quarrels  without  animosity,  75. 

sociable,  74. 

spread  of,  65. 

stays  over  winter,  79. 

successful,  83. 

transported  in  cars,  dy. 

unafraid  of  man,  69. 

wintering,  Tz. 


298 


INDEX 


Sparrow,  House,  62. 
Sphcx  wasp,   143. 
Spider  cocoons,  139. 
Spider,  young,   140. 
Spontaneous  generation,   159. 
Stone  lilies,  171. 
Story  of  the  horse,  220, 
Struggle  against  enemies,  104. 

for  food,  91. 

for  shelter,  92. 

for  the  individual,  90. 

for  the  species,  91,  125. 
Sunfish  and  young,  196. 


Taste  of  toad,  118. 
Teeth  of  mammals,  98. 
Temperature   of   mammals,  99. 
Tertiary  era,  185. 
Thayer,  concealing  color,  115. 
Theology  and  science,  280. 
Theology,  definition,  280. 
Thomas  Aquinas  and  evolution, 

12. 
Three-toed  horse,  227. 
Toad,  bad  taste,  118. 

color,  112, 

enemies,  113. 

short  tadpole  stage,  112. 
Tomato  worm,  142. 
Turtles  and  young,  202. 
Tusks  of  elephant,  124. 
Tussock  worm,  64. 


Two  methods  of  reproduction, 

194. 
Types  of  insect  mouth,  93. 

U 

Understanding  the  Bible,  281. 
Underwing  moth,   130. 


Variation  and  natural  selection, 
49. 
by  crossing,  53. 
Virchow    and    man's    ancestry, 

187. 
Vireo's  color,  115. 

W 

Wagner  and  isolation,  241. 
Wallace  and  evolution,  39. 
Warm-blooded  animals,  99. 
Weissman    and   evolution,   235. 
VVilberforce,  Bishop,  and  evolu- 
tion, 41. 
Wintering  of  ground  hog,  103. 
Wintering  of  mammals,  103. 
Wintering  of  squirrels,  103. 
Woodchuck,  103. 
Woodpecker's  nest,  146. 


Young  growing  finer,  272. 


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,:oiae*««- 


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and  present  the  subject  in  a  way  that  will  be  intelligible  to  those  unfamiliar 
with  biological  phenomena.  The  subject,  however,  is  somewhat  intricate, 
and  cannot  be  presented  in  so  simple  a  manner  as  to  require  no  thought 
on  the  reader's  part;  but  it  is  hoped  that  the  interest  of  the  subject  will 
make  the  few  hours  spent  in  the  perusal  of  this  book  a  pleasure  rather 
than  a  burden. 

In  many  instances  matter  that  might  have  been  elaborated  in  the  text 
has  been  treated  in  the  pictures,  which,  with  their  appended  explanations, 
form  an  essential  part  of  the  presentation  of  the  subject.  This  method  of 
treatment  has  been  chosen  both  for  the  sake  of  the  greater  vividness  thus 
secured  and  because  it  enables  the  book  to  be  reduced  to  the  limits  de- 
sired. Many  of  the  illustrations  have  been  obtained  from  books  with 
which  the  reader  may  wish  later  to  become  familiar. 


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THE    WORKS    OF   HENRI    BERGSON 

Professor  at  the  College  de  France 

Time  and  Free  Will 

An  Essay  on  the  Immediate  Data  of  Consciousness 

Authorized  Translation  by  F.  L.  Pogson,  New  York 

Clo^/i,  8vo,  %2.y^  net 

"The  translation  is  faithful  and  readable.  There  are  added  a  sym- 
pathetic preface  by  the  translator  and  an  admirably  comprehensive 
bibliography  of  articles  about  Bergson's  philosophy  in  several  lan- 
guages. The  first  presentation  of  this  important  contemporary  to 
our  public  has  been  so  well  done  that  all  readers  of  the  book  must 
lament  the  sudden  death  of  the  young  Oxford  scholar  to  whom  we 
owe  the  service." — Nation. 

"This  is  a  great  work,  profoundly  original,  rigorous  and  keen  in 
analysis,  clear  in  statement  ;  and  while  showing  that  language  com- 
pels us  to  treat  life  and  its  problems  in  a  symbolical  manner,  yet  it 
also  shows  that  a  close  analysis  of  experience  clearly  reveals  the  true 
concrete  life.  Professor  Bergson  does  not  profess  to  cover  the  entire 
field  of  philosophy  in  this  volume,  but  what  he  has  covered  is  done 
in  such  an  original  and  profound  way  that  no  one  who  pretends  to 
keep  abreast  of  philosophical  thought  will  ignore  it."  —  Boston  Tran- 
script. 

Matter  and  Memory 

Translated  by  Nancy  Margaret  Paul  and  W.  Scott  Palmer 

Cloth,  8vo,  XX  -\-  ^^g  pages,  index,  $2.y^  net;  by  jnail,  $2.gj 

This  translation  has  been  made  from  the  fifth  edition,  1908,  of  "Ma- 
tiere  de  Memoire,"  by  Henri  Bergson,  Member  of  the  Institute  and 
Professor  at  the  College  de  France.  It  has  the  very  great  advantage 
of  being  revised  in  proof  by  the  author.  A  new  introduction  has  also 
been  written  w^hich  supersedes  that  which  accompanied  the  original 
work.  The  reader's  attention  is  called  to  the  fact  that  all  the  mar- 
ginal notes  are  peculiar  to  the  English  edition  ;  and  that  M.  Bergson 
is  not  responsible  for  their  insertion  or  character. 

Laughter  Clot^,  $i.2S  net,-  ly  maH,  $1.34 

The  work  has  been  highly  successful  in  France,  where  it  is  in  its  sev- 
enth edition.  It  has  been  translated  into  Russian,  Polish,  and  Swed- 
ish. German  and  Hungarian  translations  are  under  preparation.  Its 
success  is  due  partly  to  the  novelty  of  the  explanation  offered  of  the 
comic,  and  partly  also  to  the  fact  that  the  author  incidentally  dis- 
cusses questions  of  still  greater  interest  and  importance. 


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Publishers  64-66  Fifth  Avenue  New  York 


